• 根据level显示哪张图片
• 在工程文件的res/drawable/新建level-list
  
  如下

<?xml version="1.0" encoding="utf-8"?>

<level-list xmlns:android="http://schemas.android.com/apk/res/android" >

    <!-- 0-10 显示这张 -->

    <item android:drawable="@drawable/wifi1"

        android:maxLevel = "10"

        ></item>

      <!-- 20-30 之间显示 -->

    <item android:drawable="@drawable/wifi2"

        android:maxLevel = "20"

        ></item>

    <item android:drawable="@drawable/wifi3"

        android:maxLevel = "30"

        ></item>

    <item android:drawable="@drawable/wifi4"

        android:maxLevel = "40"

        ></item>

</level-list>

• 使用

package com.qf.day18_uiresources_demo;

import android.app.Activity;

import android.os.Bundle;

import android.view.View;

import android.widget.ImageView;

public class LevelActivity extends Activity {

    private ImageView iv;

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        // TODO Auto-generated method stub

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_level);

        iv = (ImageView) findViewById(R.id.imageView1);

    }

    public void clickButton(View v) {

        switch (v.getId()) {

        case R.id.button1:

            iv.setImageLevel(10);

            break;

        case R.id.button2:

            iv.setImageLevel(20);

            break;

        case R.id.button3:

            iv.setImageLevel(30);

            break;

        case R.id.button4:

            iv.setImageLevel(40);

            break;

        }

    }

}