5.Android之image控件学习

Android中经常用到图片，比如图片浏览、图标等等，今天学习下image控件，image控件主要有ImageButton和ImageView两种。

(1)ImageButton

在布局文件增加：

<ImageButton
android:id="@+id/imageButton1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/textView1"
android:layout_below="@+id/textView1"
android:layout_marginTop="21dp"
android:src="@drawable/ic_launcher" />    效果：如果想改变按钮图案，可以在drawable下放自定义图标,然后修改imagebutton里面src代码即可，如图

(2)ImageView

这个稍微复杂点,但也不是很难，我们先随便添加几张图片如图：

简单修改下xml文件，

 <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:tools="http://schemas.android.com/tools"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
     android:paddingBottom="@dimen/activity_vertical_margin"
     android:paddingLeft="@dimen/activity_horizontal_margin"
     android:paddingRight="@dimen/activity_horizontal_margin"
     android:paddingTop="@dimen/activity_vertical_margin"
     tools:context="com.example.imagebutton.MainActivity" >

     <LinearLayout
         android:id="@+id/layout1"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:orientation="vertical">
     <TextView
         android:id="@+id/textView1"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:text="@string/hello_world" />

     <ImageView
         android:id="@+id/imageView1"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:layout_alignLeft="@+id/textView1"
         android:layout_below="@+id/textView1"
         android:layout_marginTop="18dp"
         android:src="@drawable/a" />

     <RadioGroup
         android:id="@+id/radioGroup1"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:layout_alignLeft="@+id/spinner1"
         android:layout_below="@+id/spinner1"
         android:layout_marginTop="29dp" >
     </RadioGroup>

     </LinearLayout>

     <Button
         android:id="@+id/button1"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:layout_alignLeft="@+id/layout1"
         android:layout_below="@+id/layout1"
         android:text="上一个" />

     <Button
         android:id="@+id/button2"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:layout_alignBottom="@+id/button1"
         android:layout_centerHorizontal="true"
         android:text="下一个" />

 </RelativeLayout>

接下来实现点击上一个或者下一个按钮，图片会发生改变功能，代码如下：

 package com.example.imagebutton;

 import android.app.Activity;
 import android.os.Bundle;
 import android.view.Menu;
 import android.view.MenuItem;
 import android.view.View;
 import android.view.View.OnClickListener;
 import android.widget.Button;
 import android.widget.ImageView;

 public class MainActivity extends Activity {

     private Button prebutton = null;
     private Button nextbutton = null;
     private ImageView imageview1 = null;
     public int i = 0;
     private int[ ] iImages = {R.drawable.a,R.drawable.b,R.drawable.c,R.drawable.d,R.drawable.e,R.drawable.f};

     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);

         prebutton = (Button)findViewById(R.id.button1);
         nextbutton = (Button)findViewById(R.id.button2);
         imageview1 = (ImageView)findViewById(R.id.imageView1);
         prebutton.setOnClickListener(new prebuttonclick());
         nextbutton.setOnClickListener(new nextbuttonclick());    

         imageview1.setImageResource(i);
     }

     public class prebuttonclick implements OnClickListener {

         @Override
         public void onClick(View v) {
             if (i > 0)
             {
                 imageview1.setImageResource(iImages[--i]);
             }
             else if (i <= 0)
             {
                 i = 5;
                 imageview1.setImageResource(iImages[i]);
             }
         }
     }

     public class nextbuttonclick implements OnClickListener {
         @Override
         public void onClick(View v) {
             if (i < 5)
             {
                 imageview1.setImageResource(iImages[++i]);
             }
             else if (i >= 5)
             {
                 i = 0;
                 imageview1.setImageResource(iImages[i]);
             }

         }
     }

     @Override
     public boolean onCreateOptionsMenu(Menu menu) {
         // Inflate the menu; this adds items to the action bar if it is present.
         getMenuInflater().inflate(R.menu.main, menu);
         return true;
     }

     @Override
     public boolean onOptionsItemSelected(MenuItem item) {
         // Handle action bar item clicks here. The action bar will
         // automatically handle clicks on the Home/Up button, so long
         // as you specify a parent activity in AndroidManifest.xml.
         int id = item.getItemId();
         if (id == R.id.action_settings) {
             return true;
         }
         return super.onOptionsItemSelected(item);
     }
 }