java - 安卓工作室 : ListView On Touch Event

Question

我正在使用 java 创建一个 android studio 应用

我的问题是:

应用在开始时崩溃并提示 NullPointerException

为什么？

因为我想在我的 ListView 上添加一个 ontouch 事件，这样我就可以得到
用户出于某些令人毛骨悚然的原因触摸的位置的 X Y

Xml

  <?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical"
    android:weightSum="1">
    <TextView

        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceMedium"
        android:text="List"
        android:id="@+id/textView"
        android:layout_centerHorizontal="true"
        android:theme="@style/Base.TextAppearance.AppCompat.Widget.ActionBar.Title"
        android:textSize="@dimen/abc_action_button_min_width_overflow_material"
        android:textStyle="normal" />
    <View
        android:layout_width="match_parent"
        android:layout_height="1dp"
        android:background="@android:color/black"
        android:layout_below="@+id/textView"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:id="@+id/textView2" />


    <ListView
        android:id="@android:id/list"
        android:layout_width="match_parent"
        android:layout_height="450dp"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:longClickable="true"
        android:layout_weight="0.65"
        android:nestedScrollingEnabled="true">
    </ListView>

    <ImageButton
        android:layout_width="55dp"
        android:layout_height="55dp"
        android:id="@+id/imageButton"
        android:layout_gravity="right"
        android:background="@drawable/trash" />


</LinearLayout>

完整代码 已更新

    package com.example.discopc.yubismart;


import android.app.AlertDialog;
import android.app.ListActivity;
import android.content.Context;
import android.content.DialogInterface;
import android.os.Bundle;
import android.view.MotionEvent;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.Toast;

import java.io.BufferedReader;
import java.io.DataOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.Socket;
import java.util.ArrayList;



public class List1 extends ListActivity {


    int x,y;
    int lx,ly;
    int width;

    public ListView list;
    public ListView list1x;

    int clicks;
    boolean isonthread;
    //ImageButton addButton;
    File file1;
    File path1;
    //LIST OF ARRAY STRINGS WHICH WILL SERVE AS LIST ITEMS
    ArrayList<String> listItems=new ArrayList<String>();

    //DEFINING A STRING ADAPTER WHICH WILL HANDLE THE DATA OF THE LISTVIEW
    ArrayAdapter<String> adapter;

    //RECORDING HOW MANY TIMES THE BUTTON HAS BEEN CLICKED
    String Fname;
    String Fip;
    int Fport;
    String Fcheck;
    String Frele;
    // int clickCounter=0;
    // int n=0;
    // int last;
    int num=0;
    // int flag1=0;
    int[] first=new int[1000];
    int[] end=new  int[1000];
    String line;
    //String[] str = {"Lamp","Fridge","TV","Laptop","Charger","Switch","Door"};
    char[]charline=new char[1000];
    boolean connected;
    String ip1;
    String s_port1;
    String name;
    String rele;
    String check;
    int port1 = 0;
    int ipflag = 0;
    int portflag = 0;
    int portnum = 0;
    char[] charip1 = new char[100];
    char[] charport1 = new char[100];
    char[] charname =new char[100];
    char[] charrele = new char[100];
    char[] charcheck = new char[100];
    int ipnum = 0;
    int checknum = 0;
    char[]chardata1 = new char[100];
    String data1="";
    int datanum;
    int j = 0;
    int num2;
    int checkname=0;
    int checkrele=0;
    int nameflag = 0;
    Socket socket;
    int releflag = 0;
    //int checkflag = 0;
    int namenum = 0;
    int relenum;
    int posi=0;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_list);
        clicks = 0;
        isonthread = false;
        list = (ListView) findViewById(R.id.list);
        adapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, listItems);
        setListAdapter(adapter);
        //listItems.add("New Item");

        loadlist();

        //This Is The Problem ! \/ \/ \/
        list.setOnTouchListener(new View.OnTouchListener() {

            @Override
            public boolean onTouch(View arg0, MotionEvent event) {
                int actionX = (int) event.getX();
                int actionY = (int) event.getY();
                int extraTapArea = 13;
                x = (int) (actionX + extraTapArea);
                y = (int) (actionY - extraTapArea);

                return false;
            }
        });
        //This Is The Problem ! /\ /\ /\

        adapter.notifyDataSetChanged();
    }



    protected void onListItemClick(ListView l, View v, final int position, long id) {




        clicks++;
        posi=position;


        lx=x;
        ly=y;



        Toast.makeText(List1.this, lx+" : "+ly,
                Toast.LENGTH_SHORT).show();


        if(!isonthread) {
            isonthread=true;
            new Thread(new Runnable() {
                public void run() {

                    try {

                        try {
                            Thread.sleep(200);
                        } catch (InterruptedException e) {

                        }

                        if ((x-lx)*(x-lx)+(y-ly)*(y-ly)<100) {
                            clicks = 0;
                            List1.this.runOnUiThread(new Runnable() {
                                public void run() {
                                    AlertDialog.Builder adb2 = new AlertDialog.Builder(List1.this);
                                    adb2.setTitle("Action :");
                                    adb2.setMessage("Remove ? " + posi);

                                    adb2.setNegativeButton("Remove", new AlertDialog.OnClickListener() {
                                        public void onClick(DialogInterface dialog, int which) {
                                            removeitem(posi);
                                        }
                                    });
                                    adb2.setPositiveButton("Cancel", new AlertDialog.OnClickListener() {
                                        public void onClick(DialogInterface dialog, int which) {

                                        }
                                    });
                                    adb2.show();
                                }
                            });
                            isonthread=false;
                        } else {
                            clicks = 0;
                            List1.this.runOnUiThread(new Runnable() {
                                public void run() {
                                    AlertDialog.Builder adb = new AlertDialog.Builder(List1.this);
                                    adb.setTitle("Action :");
                                    adb.setMessage("Connect " + posi);
                                    final int positionToRemove = posi;
                                    adb.setNegativeButton("Connect", new AlertDialog.OnClickListener() {
                                        public void onClick(DialogInterface dialog, int which) {
                                            posi = posi;
                                            testconnection();
                                        }
                                    });
                                    adb.setPositiveButton("Cancel", new AlertDialog.OnClickListener() {
                                        public void onClick(DialogInterface dialog, int which) {

                                        }
                                    });
                                    adb.show();
                                }
                            });
                            isonthread=false;
                        }

                    } catch (Exception e) {

                    }

                }
            }).start();
        }
    }


    public void testconnection(){
        try {
            //isChecked=false;
            for (int i = 0; i <= 99; i++) {
                charport1[i]='\0';
                charip1[i]='\0';
                charname[i]='\0';
                //charcheck[i]='\0';
                charrele[i]='\0';
            }
            //connected=false;
            num=0;
            num2=0;


            line=Read1();
            charline=line.toCharArray();
            for (int i=0;i<=charline.length-1;i++){
                if (charline[i]=='*'){
                    first[num]=i;
                    num++;
                }
                if (charline[i]=='#') {
                    end[num2]=i;
                    num2++;
                }
            }

            //super.onListItemClick(l, v, pos, id);
            //Toast.makeText(this, str[position] + line, Toast.LENGTH_SHORT).show();
            ipnum=0;
            portnum=0;
            datanum=0;
            namenum=0;
            relenum=0;
            releflag=0;

            for (int i = first[posi]; i <= end[posi]-1; i++) {
                analyse(i);
            }
            //Toast.makeText(this, str[position] + datanum+"", Toast.LENGTH_SHORT).show();
            j=0;
            //   Toast.makeText(this, str[position] + " S2FOR", Toast.LENGTH_SHORT).show();
            //for (int i=checkname;i<=(checkrele-3);i++){
            //charline[i]=charname[j];
            //j++;
            //}

            convert_to_string_all();

            ip1=ip1.replace(":","");
            ip1=ip1.replaceAll("[^\\d.]","");
            s_port1=s_port1.replaceAll("[\\D]","");
            name=name.replace("$","");
            //Toast.makeText(this, "-"+ip1+"-", LENGTH_SHORT).show();
            Fname=name;
            Fip=ip1;
            Fcheck=check;
            Fport=port1;
            Frele=rele;

            int portnew;
            portnew = Integer.parseInt(s_port1);
            port1= portnew;
            //Toast.makeText(this, "-"+portnew+"-", LENGTH_SHORT).show();

            j=0;
            new Thread(new Runnable() {
                public void run() {
                    try {

                        //###############################################################//
                        //###############################################################//
                        //            ============== Connect ==============              //
                        //###############################################################//
                        InetAddress serverAddr = InetAddress.getByName(ip1);
                        InetSocketAddress addz = new InetSocketAddress(ip1, port1);
                        socket = new Socket(serverAddr, port1);

                        DataOutputStream dos = new DataOutputStream(socket.getOutputStream());
                        BufferedReader dis = new BufferedReader(new InputStreamReader(socket.getInputStream()));


                        connected=true;

                        //check = check.replace("no", "ok");
                        check="ok";
                        charcheck=check.toCharArray();
                        List1.this.runOnUiThread(new Runnable() {
                            public void run() {
                                //Toast.makeText(this, "wrong", Toast.LENGTH_SHORT).show();
                                //Toast.makeText(MainActivity.this, check, LENGTH_SHORT).show();
                            }
                        });
                        List1.this.runOnUiThread(new Runnable() {
                            public void run() {
                                //Toast.makeText(this, "wrong", Toast.LENGTH_SHORT).show();
                                //Toast.makeText(MainActivity.this, name, LENGTH_SHORT).show();
                            }
                        });

                        chardata1=data1.toCharArray();
                        j=0;
                        for (int i=checknum;i<=checkname-3;i++){
                            charline[i]=charcheck[j];
                            j++;
                        }
                        String fixline = new String(charline);
                        line = fixline;
                        Write1(line);
                        //###############################################################//
                    } catch (final Exception e) {
                        connected=false;
                        check="no";
                        charcheck=check.toCharArray();
                        List1.this.runOnUiThread(new Runnable() {
                            public void run() {
                                //Toast.makeText(MainActivity.this, check, LENGTH_SHORT).show();
                            }
                        });
                        List1.this.runOnUiThread(new Runnable() {
                            public void run() {
                                //Toast.makeText(MainActivity.this, name, LENGTH_SHORT).show();
                            }
                        });

                        chardata1=data1.toCharArray();
                        j=0;
                        for (int i=checknum;i<=checkname-3;i++){
                            charline[i]=charcheck[j];
                            j++;
                        }
                        String fixline = new String(charline);
                        line = fixline;
                        Write1(line);
                        List1.this.runOnUiThread(new Runnable() {
                            public void run() {
                                //Toast.makeText(this, "wrong", Toast.LENGTH_SHORT).show();

                            }
                        });

                    }

                }
            }).start();


            //dos = new DataOutputStream(socket.getOutputStream());
            //dis = new BufferedReader(new InputStreamReader(socket.getInputStream()));*/
        }
        catch (Exception e)
        {
            connected=false;
        }
    }
    public void analyse(int i){
        if (releflag==1)
        {

            charrele[relenum]=charline[i];
            relenum++;
        }

        if (nameflag==1){
            charname[namenum]=charline[i];
            namenum++;
        }
        if (portflag == 1) {
            charport1[portnum] = charline[i];
            portnum++;
        }
        if (ipflag == 1) {
            charip1[ipnum] = charline[i];
            ipnum++;
        }
        if (charline[i]=='$'){
            checkrele=i+1;
            nameflag=0;
            releflag=1;
        }
        if (charline[i]=='*'){
            ipflag=1;
        }
        if (charline[i] == ':') {
            ipflag = 0;
            portflag = 1;
        }
        if (charline[i]=='^'){
            nameflag=1;
            checkname=i+1;

        }
        if (charline[i] == '@') {
            checknum=i+1;
            portflag=0;
        }
        if (charline[i] == '#') {
            releflag=0;
        }
        chardata1[datanum]=charline[i];
        datanum++;
    }
    public void removeitem(final int position){
        final int positionToRemove = position;
        listItems.remove(positionToRemove);
        adapter.notifyDataSetChanged();
        try{
            for (int i = 0; i <= 99; i++) {
                charport1[i]='\0';
                charip1[i]='\0';
                charname[i]='\0';
                //charcheck[i]='\0';
                charrele[i]='\0';
            }
            //connected=false;
            num=0;
            num2=0;

            line=Read1();
            charline=line.toCharArray();
            for (int i=0;i<=charline.length-1;i++){
                if (charline[i]=='*'){
                    first[num]=i;
                    num++;
                }
                if (charline[i]=='#') {
                    end[num2]=i;
                    num2++;
                }
            }
            for (int i = first[position]; i <= end[position]; i++) {
                charline[i]='\0';
            }
            String fixline = new String(charline);
            line = fixline;
            Write1(line);
        }catch (Exception e){};
    }
    public void loadlist(){
        try {
            for (int i = 0; i <= 99; i++) {
                charport1[i] = '\0';
                charip1[i] = '\0';
                charname[i] = '\0';
                //charcheck[i]='\0';
                charrele[i] = '\0';
            }
            //connected=false;
            num = 0;
            num2 = 0;

            line = Read1();
            charline = line.toCharArray();
            for (int i = 0; i <= charline.length - 1; i++) {
                if (charline[i] == '*') {
                    first[num] = i;
                    num++;
                }
                if (charline[i] == '#') {
                    end[num2] = i;
                    num2++;
                }
            }
            //Toast.makeText(this, str[position] + line, Toast.LENGTH_SHORT).show();
            ipnum = 0;
            portnum = 0;
            datanum = 0;
            namenum = 0;
            relenum = 0;
            for (int i = 0; i <= 99; i++) {
                charport1[i]='\0';
                charip1[i]='\0';
                charname[i]='\0';
                //charcheck[i]='\0';
                charrele[i]='\0';
            }
            for (int p = 0; p <= num-1; p++) {
                ipnum = 0;
                portnum = 0;
                datanum = 0;
                namenum = 0;
                relenum=0;
                releflag=0;
                for (int i = 0; i <= 99; i++) {
                    charport1[i]='\0';
                    charip1[i]='\0';
                    charname[i]='\0';
                    //charcheck[i]='\0';
                    charrele[i]='\0';
                }
                for (int i = first[p]; i <= end[p]; i++) {
                    analyse(i);
                }
                j=0;
                //   Toast.makeText(this, str[position] + " S2FOR", Toast.LENGTH_SHORT).show();
                /*for (int i=checkname;i<=(checkrele-3);i++){
                    charline[i]=charname[j];
                    j++;
                }*/
                convert_to_string_all();


                ip1 = ip1.replace(":", "");
                //  s_port1=s_port1.replace("@","");
                ip1 = ip1.replaceAll("[^\\d.]", "");
                s_port1 = s_port1.replaceAll("[\\D]", "");
                name=name.replace("$","");
                listItems.add(name + "\n" + ip1 + "       " + s_port1);
                adapter.notifyDataSetChanged();
            }

        } catch (Exception e) {
        }
    }
    public  void  convert_to_string_all(){
        String fixrele = new String(charrele);
        rele = fixrele;
        String fixdata = new String(chardata1);
        data1 = fixdata;
        String fixline = new String(charline);
        line = fixline;
        String fixip = new String(charip1);
        ip1 = fixip;
        String fixport = new String(charport1);
        s_port1 = fixport;
        String fixname = new String(charname);
        name = fixname;
    }


    private void Write1(String data) {
        try {
            Context context = getApplicationContext();
            if(path1==null)path1 = context.getFilesDir();
            file1 = new File(path1, "first.txt");
            FileOutputStream stream = new FileOutputStream(file1);
            try {
                stream.write(data.getBytes());
            } finally {
                stream.close();
            }
        }
        catch (IOException e) {

        }
    }
    private String Read1() throws IOException {

        String ret = "";
        Context context = getApplicationContext();
        if(path1==null)path1 = context.getFilesDir();
        file1 = new File(context.getFilesDir(), "first.txt");


        int length = (int) file1.length();

        byte[] bytes = new byte[length];

        FileInputStream in = new FileInputStream(file1);
        try {
            in.read(bytes);
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            in.close();
        }

        String contents = new String(bytes);
        ret=contents;
        return ret;
    }
}

更新后的代码可能令人毛骨悚然:D

我想要什么？我想在 ListView 中获得触摸位置

抱歉英语不好!

• logcat (我不知道要准确复制什么，我不能复制所有因为它扩展了正文的最大字符数)

  07-18 14:17:06.010 7805-7805/com.example.discopc.yubismart W/dalvikvm:VFY:无法解析虚拟方法 402:Landroid/content/res/TypedArray;.getType (I)I07-18 14:17:18.680 7805-7805/com.example.discopc.yubismart W/dalvikvm:threadid=1:线程退出并出现未捕获的异常(group=0x41660c50)

Answer 1

您应该使用 onItemClick，当您使用 onTouch 时，它会在您触摸 listView 时触发

listView.setOnItemClickListener(new OnItemClickListener() {
            public void onItemClick(AdapterView<?> parent, View view,
                    int position, long id) {


            }
        });