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，

 1 <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
 2     xmlns:tools="http://schemas.android.com/tools"
 3     android:layout_width="match_parent"
 4     android:layout_height="match_parent"
 5     android:paddingBottom="@dimen/activity_vertical_margin"
 6     android:paddingLeft="@dimen/activity_horizontal_margin"
 7     android:paddingRight="@dimen/activity_horizontal_margin"
 8     android:paddingTop="@dimen/activity_vertical_margin"
 9     tools:context="com.example.imagebutton.MainActivity" >
10     
11     <LinearLayout 
12         android:id="@+id/layout1"
13         android:layout_width="wrap_content"
14         android:layout_height="wrap_content"
15         android:orientation="vertical">
16     <TextView
17         android:id="@+id/textView1"
18         android:layout_width="wrap_content"
19         android:layout_height="wrap_content"
20         android:text="@string/hello_world" />
21 
22     <ImageView
23         android:id="@+id/imageView1"
24         android:layout_width="wrap_content"
25         android:layout_height="wrap_content"
26         android:layout_alignLeft="@+id/textView1"
27         android:layout_below="@+id/textView1"
28         android:layout_marginTop="18dp"
29         android:src="@drawable/a" />
30 
31     <RadioGroup
32         android:id="@+id/radioGroup1"
33         android:layout_width="wrap_content"
34         android:layout_height="wrap_content"
35         android:layout_alignLeft="@+id/spinner1"
36         android:layout_below="@+id/spinner1"
37         android:layout_marginTop="29dp" >
38     </RadioGroup>
39     
40     </LinearLayout>
41 
42     <Button
43         android:id="@+id/button1"
44         android:layout_width="wrap_content"
45         android:layout_height="wrap_content"
46         android:layout_alignLeft="@+id/layout1"
47         android:layout_below="@+id/layout1"
48         android:text="上一个" />
49 
50     <Button
51         android:id="@+id/button2"
52         android:layout_width="wrap_content"
53         android:layout_height="wrap_content"
54         android:layout_alignBottom="@+id/button1"
55         android:layout_centerHorizontal="true"
56         android:text="下一个" />
57 
58 </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：

 1 package com.example.imagebutton;
 2 
 3 import android.app.Activity;
 4 import android.os.Bundle;
 5 import android.view.Menu;
 6 import android.view.MenuItem;
 7 import android.view.View;
 8 import android.view.View.OnClickListener;
 9 import android.widget.Button;
10 import android.widget.ImageView;
11 
12 public class MainActivity extends Activity {
13     
14     private Button prebutton = null;
15     private Button nextbutton = null;
16     private ImageView imageview1 = null;
17     public int i = 0;
18     private int[ ] iImages = {R.drawable.a,R.drawable.b,R.drawable.c,R.drawable.d,R.drawable.e,R.drawable.f};
19     
20     @Override
21     protected void onCreate(Bundle savedInstanceState) {
22         super.onCreate(savedInstanceState);
23         setContentView(R.layout.activity_main);
24         
25         prebutton = (Button)findViewById(R.id.button1);
26         nextbutton = (Button)findViewById(R.id.button2);
27         imageview1 = (ImageView)findViewById(R.id.imageView1);
28         prebutton.setOnClickListener(new prebuttonclick());
29         nextbutton.setOnClickListener(new nextbuttonclick());    
30         
31         imageview1.setImageResource(i);
32     }
33     
34 
35     public class prebuttonclick implements OnClickListener {
36         
37         @Override
38         public void onClick(View v) {
39             if (i > 0)
40             {     
41                 imageview1.setImageResource(iImages[--i]);
42             }
43             else if (i <= 0)
44             {
45                 i = 5;
46                 imageview1.setImageResource(iImages[i]);
47             }
48         }
49     }
50     
51     
52     public class nextbuttonclick implements OnClickListener {
53         @Override
54         public void onClick(View v) {
55             if (i < 5) 
56             {
57                 imageview1.setImageResource(iImages[++i]);    
58             }
59             else if (i >= 5)
60             { 
61                 i = 0;
62                 imageview1.setImageResource(iImages[i]);
63             }
64 
65         }
66     }
67 
68     @Override
69     public boolean onCreateOptionsMenu(Menu menu) {
70         // Inflate the menu; this adds items to the action bar if it is present.
71         getMenuInflater().inflate(R.menu.main, menu);
72         return true;
73     }
74 
75     @Override
76     public boolean onOptionsItemSelected(MenuItem item) {
77         // Handle action bar item clicks here. The action bar will
78         // automatically handle clicks on the Home/Up button, so long
79         // as you specify a parent activity in AndroidManifest.xml.
80         int id = item.getItemId();
81         if (id == R.id.action_settings) {
82             return true;
83         }
84         return super.onOptionsItemSelected(item);
85     }
86 }