使用ImageButton.setImageResource加載圖像

上一篇文章闡釋了如何使用XML定義ImageButton, 亦可以使用程式碼實現類似的效果.


預先準備三個按鈕的圖像, 分別顯示normal, focused 和 pressed 三種狀態, 並且儲存到/res/drawable-mdpi/文件夾中.



修改佈局文件(/res/layout/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:layout_width="fill_parent"
  android:layout_height="wrap_content"
  android:text="@string/hello"
  />
<ImageButton
  android:id="@+id/imagebutton"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:background="@drawable/normal"
  />
</LinearLayout>

在主程序重寫setOnFocusChangeListener()和setOnClickListener(), 使用ImageButton.setImageResource加載圖像.

package com.AndroidImageButton;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.ImageButton;

public class AndroidImageButton extends Activity {

ImageButton imageButton;

  /** Called when the activity is first created. */
  @Override
  public void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.main);
    
      imageButton = (ImageButton)findViewById(R.id.imagebutton);
    
      imageButton.setOnClickListener(imageButtonOnClickListener);
      imageButton.setOnFocusChangeListener(imageButtonOnFocusChangeListener);
  }

  private ImageButton.OnClickListener imageButtonOnClickListener
   = new ImageButton.OnClickListener(){

  @Override
  public void onClick(View v) {
   // TODO Auto-generated method stub
   imageButton.setImageResource(R.drawable.pressed);
  }
  
  };

  private ImageButton.OnFocusChangeListener imageButtonOnFocusChangeListener
   = new ImageButton.OnFocusChangeListener(){

  @Override
  public void onFocusChange(View v, boolean hasFocus) {
   // TODO Auto-generated method stub
   if (hasFocus==true)
   {
    imageButton.setImageResource(R.drawable.focused);
   }
   else
   {
    imageButton.setImageResource(R.drawable.normal);
   }
  }
  
  };
}