4.2设计具有背景图的按钮—ImageButton的焦点及事件处理

目录

4.2设计具有背景图的按钮—ImageButton的焦点及事件处理... 1

目标:1

方法:1

代码:1

效果:3

问题：... 3

 

 

目标:设计具有背景图的按钮

方法:ImageButton的 onFocusChange方法,onClick方法

代码:

package edu.cquptzx.ImageButton;

import android.app.Activity;

import android.os.Bundle;

import android.view.View;

import android.view.View.OnClickListener;

import android.view.View.OnFocusChangeListener;

import android.widget.Button;

import android.widget.ImageButton;

import android.widget.TextView;

 

publicclass ImageButtonActivity extends Activity {

    private ImageButton ib;

    private Button btn;

    private TextView tv;

    /** Called when the activity is first created. */

    publicvoid onCreate(Bundle savedInstanceState)

    {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.main);

       

        /*Find the objects by IDs.*/

        ib = (ImageButton) findViewById(R.id.imageButton);

        btn= (Button) findViewById(R.id.button);

        tv = (TextView) findViewById(R.id.statusText);

       

        final  String str_textView = getString(R.string.textView);

        final  String str_status_FOCUSED = getString(R.string.status_FOCUSED);

        final  String str_status_LOSTFOCUSED = getString(R.string.status_LOSTFOCUSED);

        final  String str_GOTCLICK = getString(R.string.status_GOTCLICK);

 

       

        /*Add an listener to the ImageButton to response the OnFocus Event. */

        ib.setOnFocusChangeListener(new OnFocusChangeListener()

      

             {

                  publicvoid onFocusChange(View v, boolean hasFocus)

                  {

                     /*IF ImageButton's status change , replace the pic and text. */

                     System.out.println("A");

                     if( v.isFocused() == true)

                     {

                         System.out.println("B");

                         tv.setText(str_textView + str_status_FOCUSED);

                         ib.setImageResource(R.drawable.iconfull);

                     }

                     else

                     {

                         System.out.println("C");

                         tv.setText(str_textView + str_status_LOSTFOCUSED);

                         ib.setImageResource(R.drawable.iconempty);

                     }                   

                  }                  

             });

        ib.setOnClickListener(new OnClickListener()

               {

                  publicvoid onClick(View v)

                  {

                     System.out.println("D");

                     tv.setText(str_textView + str_GOTCLICK);

                     ib.setImageResource(R.drawable.iconfull);

                  }             

               });

        btn.setOnClickListener(new OnClickListener()

               {

                  publicvoid onClick(View v)

                  {  

                     System.out.println("E");

                     tv.setText(str_textView + str_status_LOSTFOCUSED);

                     ib.setImageResource(R.drawable.iconempty);

                  }             

               });

       

    }

}

效果:

问题：

onFocusChange方法并没有起到作用,从LogCat里面可以看出来: