java - 带有 ArrayAdapter 的 Android ListView 不显示任何内容

Question

我知道有很多关于如何制作 Android ListView 的帖子，但即使浏览了其中的大部分，我也无法弄清楚我的问题是什么。我是 Android 的新手，显然有点不知所措。 Activity 运行但不显示任何内容。

这是我的 Activity :

package com.example.myfirstapp;

import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.ListView;

public class HistoryActivity extends Activity {

CustomRowAdapter customRowAdapter;  
ListView listView;

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

    listView = (ListView)findViewById(R.id.listView);
    customRowAdapter = new CustomRowAdapter(getApplicationContext());
    listView.setAdapter(customRowAdapter);

}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.history, 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);
}
}

这是 activity_history.xml:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingLeft="16dp"
android:paddingRight="16dp"
android:orientation="vertical"> 

<ListView
    android:id="@+id/listView"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content" />

</LinearLayout>

ListView 中输入的 xml (custom_row.xml):

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingLeft="16dp"
android:paddingRight="16dp"
android:orientation="vertical"> 

 <TextView
    android:id="@+id/textView1"
    android:background="@drawable/box"
    android:textSize="18sp"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:text="@string/app_name" />

 <TextView
    android:id="@+id/textView2"
    android:background="@drawable/box"
    android:textSize="18sp"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:text="@string/app_name" />

 <TextView
    android:id="@+id/textView3"
    android:background="@drawable/box"
    android:textSize="18sp"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:text="@string/app_name" />

</LinearLayout>

和 CustomRowAdapter.java:

package com.example.myfirstapp;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.TextView;

public class CustomRowAdapter extends ArrayAdapter<String> {

private String[] text1 = {
        "Google Plus",
        "Twitter", 
        "Facebook", 
        "Instagram"};

private String[] text2 = {
        "test1",
        "test2", 
        "test3", 
        "test4"};

private String[] text3 = {
        "Google Plus",
        "Twitter", 
        "Facebook", 
        "Instagram"};

private LayoutInflater layoutInflater;
private Context context;

public CustomRowAdapter(Context context) {
    super(context,0);
    layoutInflater=    (LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    this.context=context;


}
@Override
public View getView(int position, View view, ViewGroup viewGroup){
    view = layoutInflater.inflate(R.layout.custom_row,null);
    TextView textViewT1 = (TextView)view.findViewById(R.id.textView1);
    TextView textViewT2 = (TextView)view.findViewById(R.id.textView2);
    TextView textViewT3 = (TextView)view.findViewById(R.id.textView3);

//      textViewT1.setText("test");
//      textViewT2.setText(text2[0]);
//      textViewT3.setText(text3[0]);


    return view; 
}

@Override
public int getCount(){
    return 0;
}       
}

希望有人能帮帮我。

Answer 1

您的 ListView 没有显示任何内容是因为

@Override
public int getCount(){
    return 0;
}  

getCount 必须返回属于您的数据集的元素数。例如

 @Override
    public int getCount(){
        return text1.length;
    }