note 39-关于启动界面,屏幕尺寸,自适应函数,与屏幕密度

android 不会自动检测屏幕密度,  所有屏幕密度默认都当作 1 (160dpi )处理 . 因此问题就来了, 我的模拟器密度是1, 因此所有像素设置都没有问题. 但在我的屏幕密度 1.5 (240 dpi )的手机上, 所有单位都自动乘了1.5 !

幸好网上有高人:

http://www.cnblogs.com/wangtianxj/archive/2011/03/18/1988358.html

DisplayMetrics metric = new DisplayMetrics();
        getWindowManager().getDefaultDisplay().getMetrics(metric);
        int width = metric.widthPixels;  // 屏幕宽度（像素）
        int height = metric.heightPixels;  // 屏幕高度（像素）
        float density = metric.density;  // 屏幕密度（0.75 / 1.0 / 1.5）
        int densityDpi = metric.densityDpi;  // 屏幕密度DPI（120 / 160 / 240）

<supports-screens
            android:smallScreens="true"
            android:normalScreens="true"
            android:largeScreens="true"
            android:resizeable="true"
            android:anyDensity="true" />

只要加入这一句, android 就会检测你屏幕的密度,自动作出正确的换算. 否则的话, 当我设置了一个宽度为屏幕一半的图片组件, 系统会自动把它乘以 1.5 , 变得无厘头的大 !

于是我的自适应算法就成立了,根据不同屏幕组件自动适应:

LinearLayout ll=(LinearLayout)this.findViewById(R.id.button_bar);
        
        ViewGroup.LayoutParams paramButtonBar=ll.getLayoutParams();
        paramButtonBar.width=(int)(display.getWidth()*0.93);
        paramButtonBar.height=(int)(display.getWidth()*0.93*0.14);
        
        ll.setLayoutParams(paramButtonBar);
        
        
        
        
        Button bCal=(Button)this.findViewById(R.id.cal_btn);
        
        ViewGroup.LayoutParams paramsCal=bCal.getLayoutParams();
        paramsCal.width=(int)(paramButtonBar.width/3);
        paramsCal.height=paramButtonBar.height;
        
        bCal.setLayoutParams(paramsCal);

另一个话题,启动界面,也来自网上,不解释了:

 http://blog.sina.com.cn/s/blog_4d142b550100rs3f.html

<?xml version="1.0" encoding="utf-8"?>
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
       package="com.sunshine.splash"
       android:versionCode="1"
       android:versionName="1.0"&gt;
     <application android:icon="@drawable/icon" android:label="@string/app_name">
         <activity android:name=".Splash"
                   android:label="@string/app_name">
             <intent-filter>
                 <action android:name="android.intent.action.MAIN"/>
                 <category android:name="android.intent.category.LAUNCHER" />
             </intent-filter>
         </activity>
     <activity android:name="Main">
     </activity>
 </application>
     <uses-sdk android:minSdkVersion="3" />
 </manifest>

然后是JAVA代码：

package net.hlovey.splash;
 import android.app.Activity;
 import android.content.Intent;
 import android.os.Bundle;
 import android.os.Handler;
  
 public class Splash extends Activity {   
  
     private final int SPLASH_DISPLAY_LENGHT = 3000; //延迟三秒 
  
     @Override
     public void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.splash);
         new Handler().postDelayed(new Runnable(){
  
          @Override
          public void run() {
              Intent mainIntent = new Intent(Splash.this,Main.class);
              Splash.this.startActivity(mainIntent);
                  Splash.this.finish();
          }
            
         }, SPLASH_DISPLAY_LENGHT);
     }
 }

public class MyActivity extends Activity implements Runnable {
    
     private boolean isOver=false;
     private LinearLayout screenup;
     Handler handler=new Handler(){

         @Override
         public void handleMessage(Message msg) {
             // TODO Auto-generated method stub
             switch(msg.what){
             case 0:
                 //隐藏启动的View
                 screenup.setVisibility(View.GONE);
                 //取消全屏
                 getWindow().clearFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN);
                 
                 break;
             case 1:
                 Toast.makeText(getApplicationContext(), "加载中", Toast.LENGTH_SHORT).show();
                 break;
             }
             super.handleMessage(msg);
         }
         
     };
     @Override
     public void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
        
         getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
                 WindowManager.LayoutParams.FLAG_FULLSCREEN);
          
         requestWindowFeature(Window.FEATURE_NO_TITLE);
         setContentView(R.layout.main);
         screenup=(LinearLayout)findViewById(R.id.screenup);
         new Thread(this).start();
         
     }
     private void show(){
         Message msg=new Message();
         if(isOver){
             msg.what=0;
             handler.sendMessage(msg);
         }else{
             msg.what=1;
             handler.sendMessage(msg);
         }
     }
     @Override
     public void run() {
         // TODO Auto-generated method stub
         //加载数据。。。。。。。。此处没有数据加载，延时2秒
             try {
                 Thread.sleep(2000);
             } catch (InterruptedException e) {
                 // TODO Auto-generated catch block
                 e.printStackTrace();
             }
             isOver=true;
             show();
             
         }
     }