举例说明android中Bitmap、ListView以及ImageView的综合使用---显示图片并获取图片的宽和高

程序如下所示：

import android.app.Activity;

import android.graphics.Bitmap;

import android.graphics.BitmapFactory;

import android.os.Bundle;

import android.view.ContextMenu;

import android.view.ContextMenu.ContextMenuInfo;

import android.view.Menu;

import android.view.MenuItem;

import android.view.View;

import android.widget.ImageView;

import android.widget.ListView;

import android.widget.TextView;

public class A02Activity extends Activity {

private TextView tv;//用来显示图片的宽或高

private ImageView iv;//用来显示图片

private static final int CONTEXT_ITEM01=Menu.FIRST;//ListView中的各个小项目

private static final int CONTEXT_ITEM02=Menu.FIRST+1;

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

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

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

iv=(ImageView)findViewById(R.id.iv);

//把图片添加到ImageView当中

iv.setBackgroundDrawable(getResources().getDrawable(R.drawable.b));

//相当于电脑当中鼠标点击右键的功能的实现

iv.setOnCreateContextMenuListener(new ListView.OnCreateContextMenuListener(){

@Override

public void onCreateContextMenu(ContextMenu menu, View v,

ContextMenuInfo menuInfo) {

//把两个选项添加到ImageView当中

menu.add(Menu.NONE, CONTEXT_ITEM01, 0, R.string.context01);

menu.add(Menu.NONE, CONTEXT_ITEM02, 0, R.string.context02);

}

});

}

//用下面的方法来判断单击了哪个item，并获取图片的长或宽

public boolean onContextItemListener(MenuItem item){

Bitmap b=BitmapFactory.decodeResource(getResources(), R.drawable.b);

int width=b.getWidth();

int height=b.getHeight();

switch(item.getItemId()){

case CONTEXT_ITEM01:

String s01=getResources().getString(R.string.str_width)+Integer.toBinaryString(width);

tv.setText(s01);

break;

case CONTEXT_ITEM02:

String s02=getResources().getString(R.string.str_height)+Integer.toString(height);

tv.setText(s02);

break;

}

return super.onContextItemSelected(item);

}

}