java - Android 应用程序，带按钮的动态 Activity 窗口

Question

我有一个想法。

我正在尝试在 Android 应用程序中实现一项功能。我有一个编辑文本和一个按钮，如果我在编辑文本中输入 3然后按下我想要转到另一个有 3 个按钮的 Activity 的按钮。

如果我输入 10，我想转到另一个 Activity 来显示 10 个按钮。我知道如何进行这样的切换，但我不知道如何动态地进行，

我想要制作 0 到 10 之间的值，但我不想有 10 个 fragment 。

请给我解决方案来实现它..

谢谢..

到目前为止:

mainactivity.java:

 package com.example.instances_temperature;

import com.example.instances_temperature.Tabel;

import android.content.Intent;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v7.app.ActionBarActivity;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;  
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

public class MainActivity extends ActionBarActivity {


    EditText instances;
    Button ok;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        ok = (Button) findViewById(R.id.ok);
        instances = (EditText) findViewById(R.id.instances);

        ok.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                 if (instances.getText().toString().length() > 0)
                 {
                int value = Integer.parseInt(instances.getText().toString());;
                if(value > 10)
                    Toast.makeText(getApplicationContext(), "Enter a value between 0 and 10!", Toast.LENGTH_SHORT).show();
                else
                    if(value<0)
                        Toast.makeText(getApplicationContext(), "Enter a value between 0 and 10!", Toast.LENGTH_SHORT).show();
                    else
                        if(value >= 0 && value <=10)
                        {
                            schimba(v);
                        }
                 }
                 else
                 {
                     Toast.makeText(getApplicationContext(), "Enter a value between 0 and 10!", Toast.LENGTH_SHORT).show();
                 }

            }
        });


        if (savedInstanceState == null) {
            getSupportFragmentManager().beginTransaction()
                    .add(R.id.container, new PlaceholderFragment()).commit();
        }
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {

        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();
        if (id == R.id.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }

    /**
     * A placeholder fragment containing a simple view.
     */
    public static class PlaceholderFragment extends Fragment {

        public PlaceholderFragment() {
        }

        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container,
                Bundle savedInstanceState) {
            View rootView = inflater.inflate(R.layout.fragment_main, container,
                    false);
            return rootView;
        }
    }
    public void schimba(View view){
        int value = Integer.parseInt(instances.getText().toString());;
        Intent intent = new Intent(this, Tabel.class);
        intent.putExtra("max", value);
        startActivity(intent);
    }

}

activity_main.xml:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/container"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.example.instances_temperature.MainActivity"
    tools:ignore="MergeRootFrame" >

    <TextView
        android:id="@+id/ShowValue"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="139dp"
        android:text="Instances No.:"
        android:textAppearance="?android:attr/textAppearanceLarge" />

    <EditText
        android:id="@+id/instances"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_centerVertical="true"
        android:ems="10"
        android:inputType="number" >

        <requestFocus />
    </EditText>

    <Button
        android:id="@+id/ok"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/instances"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="48dp"
        android:text="Ok"
        android:onClick="schimba" />

</RelativeLayout>

tabel.java:

    package com.example.instances_temperature;

import android.support.v7.app.ActionBarActivity;
import android.support.v7.app.ActionBar;
import android.support.v4.app.Fragment;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.LinearLayout;
import android.widget.TextView;
import android.os.Build;

public class Tabel extends ActionBarActivity {

    int i;

    int value;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_tabel);
        Intent intentObject = getIntent();
        value = intentObject.getIntExtra("max", 0);
        LinearLayout layout = (LinearLayout)findViewById(R.id.container);

        for(i=1;i<=value;i++)
        {
            LayoutInflater layoutinflate = null; 
            layoutinflate = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE); 
            final View rowview = layoutinflate.inflate( R.layout.ShowMe, null);

            TextView showvalue;
            showvalue = (TextView) rowview.findViewById(R.id.showid);
            showvalue.setText(""+value);

            layout.addView(rowview);
        }



        //showvalue.setText(String.valueOf(getIntent().getExtras().getInt("max")));


        if (savedInstanceState == null) {
            getSupportFragmentManager().beginTransaction()
                    .add(R.id.container, new PlaceholderFragment()).commit();
        }
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {

        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.tabel, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();
        if (id == R.id.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }

    /**
     * A placeholder fragment containing a simple view.
     */
    public static class PlaceholderFragment extends Fragment {

        public PlaceholderFragment() {
        }

        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container,
                Bundle savedInstanceState) {
            View rootView = inflater.inflate(R.layout.fragment_tabel,
                    container, false);
            return rootView;
        }
    }

}

activity_tabel.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/container"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context="com.example.instances_temperature.Tabel"
    tools:ignore="MergeRootFrame" >

</LinearLayout>

inflation_layout.xml的LinearLayout代码

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/inflationn"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <TextView
        android:id="@+id/ShowMe"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Large Text"
        android:textAppearance="?android:attr/textAppearanceLarge" />

</LinearLayout>

LogCat 错误:

04-24 06:21:04.244: E/AndroidRuntime(269): FATAL EXCEPTION: main
04-24 06:21:04.244: E/AndroidRuntime(269): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.instances_temperature/com.example.instances_temperature.Tabel}: java.lang.NullPointerException
04-24 06:21:04.244: E/AndroidRuntime(269):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663)
04-24 06:21:04.244: E/AndroidRuntime(269):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
04-24 06:21:04.244: E/AndroidRuntime(269):  at android.app.ActivityThread.access$2300(ActivityThread.java:125)
04-24 06:21:04.244: E/AndroidRuntime(269):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
04-24 06:21:04.244: E/AndroidRuntime(269):  at android.os.Handler.dispatchMessage(Handler.java:99)
04-24 06:21:04.244: E/AndroidRuntime(269):  at android.os.Looper.loop(Looper.java:123)
04-24 06:21:04.244: E/AndroidRuntime(269):  at android.app.ActivityThread.main(ActivityThread.java:4627)
04-24 06:21:04.244: E/AndroidRuntime(269):  at java.lang.reflect.Method.invokeNative(Native Method)
04-24 06:21:04.244: E/AndroidRuntime(269):  at java.lang.reflect.Method.invoke(Method.java:521)
04-24 06:21:04.244: E/AndroidRuntime(269):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
04-24 06:21:04.244: E/AndroidRuntime(269):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
04-24 06:21:04.244: E/AndroidRuntime(269):  at dalvik.system.NativeStart.main(Native Method)
04-24 06:21:04.244: E/AndroidRuntime(269): Caused by: java.lang.NullPointerException
04-24 06:21:04.244: E/AndroidRuntime(269):  at com.example.instances_temperature.Tabel.onCreate(Tabel.java:42)
04-24 06:21:04.244: E/AndroidRuntime(269):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
04-24 06:21:04.244: E/AndroidRuntime(269):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)
04-24 06:21:04.244: E/AndroidRuntime(269):  ... 11 more

Answer 1

您可以通过以下方式从 editText 获取值

String value= EditText.getText().toString();

通过Intent将值传递给另一个 Activity (Activity2)

现在在 Activity2 中，您在 onCreate() 中编写此代码

for(int i=1 ; i<= value ; i++){
    Button b = new Button(getApplicationContext());           
    LinearLayout.addView(b);
}