android基于监听的事件处理

android利用监听器来实现事件处理，有多种方法：

//以下下import 包部分省略，复制时请自行导入

1. Activity本身作为事件监听器

activity_main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.testevent.MainActivity" >

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/hello_world" />

    <Button
        android:id="@+id/button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/textView1"
        android:layout_below="@+id/textView1"
        android:text="Button" />

</RelativeLayout>

MainActivity.java

public class MainActivity extends Activity implements OnClickListener{
	TextView textView;
	Button button;
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		textView = (TextView) findViewById(R.id.textView1);
		button = (Button) findViewById(R.id.button1);
		button.setOnClickListener(this);
	}

	@Override
	public void onClick(View v) {
		textView.setText("我被点击了");
	}

}

2.匿名内部类作为事件监听器

xml文件同上

MainActivity.java

public class MainActivity extends Activity {
	Button button;
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		button = (Button) findViewById(R.id.button1);
		button.setOnClickListener(new OnClickListener() {
			
			@Override
			public void onClick(View v) {
				TextView textView = (TextView) findViewById(R.id.textView1);
				textView.setText("我被点击了");
			}
		});
	}

}

3.定义外部类作为事件监听器

xml文件同上

MainActivity.java

public class MainActivity extends Activity {
	TextView textView;
	Button button;
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		textView = (TextView)findViewById(R.id.textView1);
		button = (Button) findViewById(R.id.button1);
		button.setOnLongClickListener(new TextChangeListener(this, textView));
	}

}

TextChangeListener.java

public class TextChangeListener implements OnLongClickListener {
	TextView textView;
	public TextChangeListener(Activity ac, TextView textView) {
		this.textView = textView;
	}

	@Override
	public boolean onLongClick(View v) {
		textView.setText("我被长时间点击了");
		return true;
	}

}

4.将事件监听器直接绑定到标签

activity_main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.testevent.MainActivity" >

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/hello_world" />

    <Button
        android:id="@+id/button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/textView1"
        android:layout_below="@+id/textView1"
        android:onClick="buttonClickHandle"
        android:text="Button" />

</RelativeLayout>

MainActivity.java

public class MainActivity extends Activity {
	TextView textView;
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
	}
	//此处必须是public
	public void buttonClickHandle(View v){
		textView = (TextView)findViewById(R.id.textView1);
		textView.setText("我被点击了");
	}

}