控件：ZoomControls 缩放控制

main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" 
    android:layout_width="fill_parent"
    android:layout_height="fill_parent">
    <TextView 
        android:id="@+id/text" 
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" 
        android:text="Android控件---ZoomControls"
        android:textSize="10px" />
    <ZoomControls 
        android:id="@+id/zoomcontrols"
        android:layout_gravity="bottom" 
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />
</LinearLayout>

MyZoomControlsDemo.java

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.TextView;
import android.widget.ZoomControls;

public class MyZoomControlsDemo extends Activity {
    // 缩放组件
    private ZoomControls zoomControls;                            
    private int size = 10;    // 默认文字大小
    private TextView text;    // 文本显示组件

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        // 调用默认布局
        super.setContentView(R.layout.main);                    
        this.zoomControls = (ZoomControls) findViewById(R.id.zoomcontrols);
        // 取得组件
        this.text = (TextView) findViewById(R.id.text);            
        // 设置放大监听
        this.zoomControls.setOnZoomInClickListener(new OnZoomInClickListenerImpl());
        // 设置缩小监听
        this.zoomControls.setOnZoomOutClickListener(new OnZoomOutClickListenerImpl());                
    }

    private class OnZoomInClickListenerImpl implements OnClickListener {

        @Override
        public void onClick(View view) {
            // 更改文字大小
            MyZoomControlsDemo.this.size = size + 2;        
            // 更改文字大小
            MyZoomControlsDemo.this.text.setTextSize(size);        
        }
    }

    private class OnZoomOutClickListenerImpl implements OnClickListener {

        @Override
        public void onClick(View view) {
            // 更改文字大小
            MyZoomControlsDemo.this.size = size - 2;
            // 更改文字大小
            MyZoomControlsDemo.this.text.setTextSize(size);        
        }
    }
}