android应用开发之ImageView，SeekBar，TableHost，ProgressBar的使用

 

先让大家看一个效果图

、、

怎么样，效果炫吗？

让我们来分析一下，这种效果怎么样才能实现呢？

首先我们注意一下，上方几个横着切换的功能是TabHost

TabHost

提供选项卡（Tab页）的窗口视图容器。此对象包含两个子对象：一组是用户可以选择指定Tab页的标签；另一组是FrameLayout用来显示该Tab页的内容。通常控制使用这个容器对象，而不是设置在子元素本身的值。（译者注：即使使用的是单个元素，也最好把它放到容器对象ViewGroup里）

内部类

interfaceTabHost.OnTabChangeListener    

接口定义了当选项卡更改时被调用的回调函数

 

interface TabHost.TabContentFactory  

当某一选项卡被选中时生成选项卡的内容

 

class TabHost.TabSpec     

单独的选项卡，每个选项卡都有一个选项卡指示符,内容和tag标签,以便于记录.

 

公共方法

public void addTab(TabHost.TabSpec tabSpec)

新增一个选项卡

参数

tabSpec   指定怎样创建指示符和内容.

 <?xml version="1.0" encoding="utf-8"?>
 <TabHost xmlns:android="http://schemas.android.com/apk/res/android"
     android:layout_width="fill_parent"
     android:layout_height="fill_parent" >

     <LinearLayout android:id="@+id/tab1" android:orientation="vertical"
         android:layout_width="fill_parent" android:layout_height="fill_parent">
         <Button android:id="@+id/button" android:layout_width="fill_parent"
             android:layout_height="wrap_content" android:text="切换到第3个标签" />
         <ImageView  android:layout_width="fill_parent"
             android:layout_height="wrap_content" android:src="@drawable/background" android:layout_marginTop="30dp"/>
     </LinearLayout>
 </TabHost>

 import android.app.TabActivity;
 import android.content.Intent;
 import android.os.Bundle;
 import android.view.LayoutInflater;
 import android.widget.TabHost;

 public class TableHostTest extends TabActivity {

     private TabHost tabHost = null;

     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         tabHost = this.getTabHost();
         LayoutInflater inflater = LayoutInflater.from(this);
         /*注意true的作用*/
         inflater.inflate(R.layout.tablehost, tabHost.getTabContentView(),true);
         tabHost.addTab(tabHost.newTabSpec("tab1").setIndicator("界面1").setContent(R.id.tab1));
         tabHost.addTab(tabHost.newTabSpec("tab2").setIndicator("界面2").setContent(new Intent(this,SeekBarDemo.class)));
         tabHost.addTab(tabHost.newTabSpec("tab3").setIndicator("界面3").setContent(new Intent(this,UITest4Activity.class)));
     }

 }

进度条显示：

<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="fill_parent" android:orientation="vertical" > <TextView android:layout_width="fill_parent" android:layout_height="wrap_content" android:text="进度条演示" /> <ProgressBar android:layout_width="wrap_content" android:layout_height="wrap_content" android:max="1000" android:progress="100" android:id="@+id/progressbar1" /> <ProgressBar style="@android:style/Widget.ProgressBar.Horizontal" android:layout_marginTop="30dp" android:layout_width="fill_parent" android:layout_height="wrap_content" android:max="1000" android:progress="500" android:secondaryProgress="300" android:id="@+id/progressbar2" /> </LinearLayout>

 import android.app.Activity;
 import android.os.Bundle;
 import android.os.Handler;
 import android.util.Log;
 import android.widget.ProgressBar;

 public class ProgressBarDemo extends Activity{

     ProgressBar progressbar = null;
     static int i = 0;
     int progressbarMax = 0;

     Handler handler = new Handler();

     public void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.progressbar_layout);

         findViews();
     }

     private void findViews() {
         progressbar = (ProgressBar) this.findViewById(R.id.progressbar2);
         progressbar.setMax(1000);
         progressbarMax = progressbar.getMax();

         new Thread(new Runnable(){

             public void run(){
                 while(i< progressbarMax){
                     i=doWork();

                     handler.post(new Runnable(){

                         public void run(){
                             progressbar.setProgress(i);
                         }
                     });
                     try {
                         Thread.sleep(50);
                     } catch (InterruptedException e) {
                         // TODO Auto-generated catch block
                         e.printStackTrace();
                     }
                 }
             }
         }).start();

     }

     public int doWork(){
         Log.d("TAG", String.valueOf(i));
         return ++i;
     }

 /*  //不能用！！！！
     public void run(){
         Log.d("TAG","thread starting...");

         while(i++ < progressbarMax){
             progressbar.setProgress(i);
             try {
                 Thread.sleep(50);
             } catch (InterruptedException e) {
                 // TODO Auto-generated catch block
                 e.printStackTrace();
             }
         }
     }
     */
 }

下面用ImageView实现图片预览功能

 import android.app.Activity;
 import android.graphics.Bitmap;
 import android.graphics.drawable.BitmapDrawable;
 import android.os.Bundle;
 import android.view.MotionEvent;
 import android.view.View;
 import android.view.View.OnTouchListener;
 import android.widget.ImageView;

 public class ImageViewDemo extends Activity implements OnTouchListener {

     ImageView imageView1, imageView2;

     protected void onCreate(Bundle savedInstanceState) {
         // TODO Auto-generated method stub
         super.onCreate(savedInstanceState);
         this.setContentView(R.layout.imageview_layout);

         findViews();
     }

     private void findViews() {
         imageView1 = (ImageView) findViewById(R.id.img1);
         imageView2 = (ImageView) findViewById(R.id.img2);

         imageView1.setOnTouchListener(this);

     }

     public boolean onTouch(View v, MotionEvent event) {
         float scale = 412 / 320;

         int x = (int) (event.getX() * scale);
         int y = (int) (event.getY() * scale);

         //尝试考虑解决边界问题
         int width = (int) (100 * scale);
         int height = (int) (100 * scale);

         BitmapDrawable bitmapDrawable = (BitmapDrawable) imageView1.getDrawable();

         imageView2.setImageBitmap(Bitmap.createBitmap(bitmapDrawable.getBitmap(),
                 x,y, width, height));

         return false;
     }

 }

 <?xml version="1.0" encoding="utf-8"?>
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
     android:orientation="vertical" >

     <ImageView
         android:id="@+id/img1"
         android:layout_width="fill_parent"
         android:layout_height="300dp"
         android:background="#cccccc"
         android:src="@drawable/pig" />

     <ImageView
         android:id="@+id/img2"
         android:layout_width="100dp"
         android:layout_height="100dp"
         android:background="#cccccc"
         android:scaleType="fitStart"
         android:layout_marginTop="20dp"
         />

 </LinearLayout>

调节音量等的控制条：

 <?xml version="1.0" encoding="utf-8"?>
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
     android:orientation="vertical" >

     <SeekBar
         android:layout_width="fill_parent"
         android:layout_height="wrap_content"
         android:max="1000"
         android:id="@+id/seekbar"
         />

 </LinearLayout>

 import android.app.Activity;
 import android.os.Bundle;
 import android.util.Log;
 import android.widget.SeekBar;
 import android.widget.SeekBar.OnSeekBarChangeListener;

 public class SeekBarDemo extends Activity implements OnSeekBarChangeListener {

     SeekBar seekbar = null;

     protected void onCreate(Bundle savedInstanceState) {
         // TODO Auto-generated method stub
         super.onCreate(savedInstanceState);
         this.setContentView(R.layout.seekbar_layout);

         findViews();
     }

     private void findViews() {
         seekbar = (SeekBar) this.findViewById(R.id.seekbar);
         seekbar.setOnSeekBarChangeListener(this);
     }

     @Override
     public void onProgressChanged(SeekBar seekBar, int progress,
             boolean fromUser) {
         Log.d("TAG", "changed: "+  String.valueOf(seekBar.getProgress()));

     }

     @Override
     public void onStartTrackingTouch(SeekBar seekBar) {
         Log.d("TAG", "start: "+  String.valueOf(seekBar.getProgress()));

     }

     @Override
     public void onStopTrackingTouch(SeekBar seekBar) {
         Log.d("TAG", "stop: "+  String.valueOf(seekBar.getProgress()));

     }

 }