一些android特殊用法

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    一些android特殊用法
    Android2010-05-2816:07:48阅读216评论1字号：大中小订阅
    Android特殊用法
    1.让一个图片透明：
    Bitmapbuffer=Bitmap.createBitmap(width,height,Bitmap.Config.ARGB_4444);buffer.eraseColor(Color.TRANSPARENT);
    2.直接发送邮件：
    Intentintent=newIntent(Intent.ACTION_SENDTO,Uri.fromParts("mailto","",null));
    intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
    context.startActivity(intent);
    3.程序控制屏幕变亮：
    WindowManager.LayoutParamslp=getWindow().getAttributes();
    lp.screenBrightness=100/100.0f;
    getWindow().setAttributes(lp);
    4.过滤特定文本
    Filterfilter=myAdapter.getFilter();
    filter.filter(mySearchText);
    5.scrollViewscroll停止事件
    setOnScrollListener(newOnScrollListener(){
    publicvoidonScroll(AbsListViewview,intfirstVisibleItem,intvisibleItemCount,inttotalItemCount){
    //TODOAuto-generatedmethodstub}
    publicvoidonScrollStateChanged(AbsListViewview,intscrollState){
    //TODOAuto-generatedmethodstub
    if(scrollState==0)Log.i("a","scrollingstopped...");}});}
    6.对于特定的程序发起一个关联供打开
    复制到剪贴板C/C++代码Bitmapbmp=getImageBitmap(jpg);
    Stringpath=getFilesDir().getAbsolutePath()+"/test.png";
    Filefile=newFile(path);
    FileOutputStreamfos=newFileOutputStream(file);
    bmppress(CompressFormat.PNG,100,fos);
    fos.close();
    
    Intentintent=newIntent();
    intent.setAction(android.content.Intent.ACTION_VIEW);
    intent.setDataAndType(Uri.fromFile(newFile(path)),"image/png");
    startActivity(intent);
    对于图片上边的不适用索引格式会出错。
    Intentintent=newIntent();
    intent.setAction(android.content.Intent.ACTION_VIEW);
    Filefile=newFile("/sdcard/test.mp4");
    intent.setDataAndType(Uri.fromFile(file),"video/*");
    startActivity(intent);
    
    Intentintent=newIntent();
    intent.setAction(android.content.Intent.ACTION_VIEW);
    Filefile=newFile("/sdcard/test.mp3");
    intent.setDataAndType(Uri.fromFile(file),"audio/*");
    startActivity(intent);
    7.设置文本外观
    setTextAppearance(context,android.R.style.TextAppearance_Medium);
    android:textAppearance="?android:attr/textAppearanceMedium"
    8.设置单独的发起模式：
        android:name=".ArtistActivity"
    android:label="Artist"
    android:launchMode="singleTop">
    
    
    Intenti=newIntent();
    i.putExtra(EXTRA_KEY_ARTIST,id);
    i.setClass(this,ArtistActivity.class);
    i.addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP);
    startActivity(i);
    9.创建一个圆角图片
    这个的
    主要原理其实就是利用遮罩，先创建一个圆角方框然后将图片放在下面：
    BitmapmyCoolBitmap=...;
    intw=myCoolBitmap.getWidth(),h=myCoolBitmap.getHeight();
    Bitmaprounder=Bitmap.createBitmap(w,h,Bitmap.Config.ARGB_8888);
    Canvascanvas=newCanvas(rounder);
    PaintxferPaint=newPaint(Paint.ANTI_ALIAS_FLAG);
    xferPaint.setColor(Color.RED);
    canvas.drawRoundRect(newRectF(0,0,w,h),20.0f,20.0f,xferPaint);
    xferPaint.setXfermode(newPorterDuffXfermode(PorterDuff.Mode.DST_IN));
    //然后呢实现
    canvas.drawBitmap(myCoolBitmap,0,0,null);
    canvas.drawBitmap(rounder,0,0,xferPaint);
    10.在notification上的icon上加上数字给人提示有多少个未读
    Notificationnotification=newNotification(icon,tickerText,when);
    notification.number=4;
    11背景渐变：
    首先建立文件drawable/shape.xml
    
    
        android:angle="270"/>
    
    在该文件中设置渐变的开始颜色(startColor)、结束颜色(endColor)和角度(angle)
    接着创建一个主题values/style.xml
    
    
    
    @drawable/shape
    
    
    然后在AndroidManifest.xml文件中的application或activity中引入该主题,如:
    
    该方法同样适用于控件17f8/trackback.php?tbID=259&;extra=9d45e9
    12.储存数据当你在一个实例中保存静态数据，此示例关闭后下一个实例想引用静态数据就会为null，这里呢必须重写applition
    publicclassMyApplicationextendsApplication{
    privateStringthing=null;
    publicStringgetThing(){
    returnthing;
    }
    publicvoidsetThing(Stringthing){
    this.thing=thing;}
    }
    publicclassMyActivityextendsActivity{
    privateMyApplicationapp;
    publicvoidonCreate(BundlesavedInstanceState){
    super.onCreate(savedInstanceState);
    app=((MyApplication)getApplication());
    Stringthing=app.getThing();
    }
    }