android特殊用法
16lz
2021-01-23
http://dev.10086.cn/cmdn/wiki/index.php?doc-view-2089.html
1.让一个图片透明:
Java代码- Bitmapbuffer=Bitmap.createBitmap(width,height,Bitmap.Config.ARGB_4444);buffer.eraseColor(Color.TRANSPARENT);
2. 直接发送邮件:
Java代码- Intentintent=newIntent(Intent.ACTION_SENDTO,Uri.fromParts("mailto","[email protected]",null));
- intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
- context.startActivity(intent);
3. 程序控制屏幕变亮:
Java代码- WindowManager.LayoutParamslp=getWindow().getAttributes();
- lp.screenBrightness=100/100.0f;
- getWindow().setAttributes(lp);
4. 过滤特定文本
Java代码- Filterfilter=myAdapter.getFilter();
- filter.filter(mySearchText);
5.scrollView scroll停止事件
Java代码- 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
C/C++代码- Bitmapbmp=getImageBitmap(jpg);
- Stringpath=getFilesDir().getAbsolutePath()+"/test.png";
- Filefile=newFile(path);
- FileOutputStreamfos=newFileOutputStream(file);
- bmp.compress(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
Java代码- setTextAppearance(context,android.R.style.TextAppearance_Medium);
- android:textAppearance="?android:attr/textAppearanceMedium"
8. 设置单独的发起模式:
Java代码- <activity
- android:name=".ArtistActivity"
- android:label="Artist"
- android:launchMode="singleTop">
- </activity>
- 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
Java代码- Notificationnotification=newNotification(icon,tickerText,when);
- notification.number=4;
11背景渐 变:
首先建立文件drawable/shape.xml
- <?xmlversion="1.0"encoding="utf-8"?>
- <shapexmlns:android="http://schemas.android.com/apk/res/android"android:shape="rectangle">
- <gradientandroid:startColor="#FFFFFFFF"android:endColor="#FFFF0000"
- android:angle="270"/>
- </shape>
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
- <?xmlversion="1.0"encoding="utf-8"?>
- <resources>
- <stylename="NewTheme"parent="android:Theme">
- <itemname="android:background">@drawable/shape</item>
- </style>
- </resources>
然 后在AndroidManifest.xml文件中的application或activity中引入该主题,如:
Java代码- <activityandroid:name=".ShapeDemo"android:theme="@style/NewTheme">
该 方法同样适用于控件 http://17f8.cn/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();
- }
- }
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