Android实用编程技巧代码总结

本文实例总结了android实用编程技巧。分享给大家供大家参考，具体如下：

1.让一个图片透明：

bitmap buffer = bitmap.createbitmap(width, height, bitmap.config.argb_4444);
buffer.erasecolor(color.transparent);

2.直接发送邮件：

intent intent = new intent(intent.action_sendto, uri .fromparts("mailto", "[e-mail]", null));
intent.setflags(intent.flag_activity_new_task);
context.startactivity(intent);

3.程序控制屏幕变亮：

windowmanager.layoutparams lp = getwindow().getattributes();
lp.screenbrightness = 100 / 100.0f;
getwindow().setattributes(lp);

4.过滤特定文本

filter filter = myadapter.getfilter();
filter.filter(mysearchtext);

5.scrollview scroll停止事件

setonscrolllistener(new onscrolllistener(){
public void onscroll(abslistview view, int firstvisibleitem, int visibleitemcount, int totalitemcount) {
// todo auto-generated method stub  }
public void onscrollstatechanged(abslistview view, int scrollstate) {
// todo auto-generated method stub
if(scrollstate == 0) log.i("a", "scrolling stopped...");  } });}

6. 对于特定的程序 发起一个关联供打开

bitmap bmp = getimagebitmap(jpg);
string path = getfilesdir().getabsolutepath() + "/test.png";
file file = new file(path);
fileoutputstream fos = new fileoutputstream(file);
bmp.compress( compressformat.png, 100, fos );
 fos.close();
  intent intent = new intent();
  intent.setaction(android .content.intent.action_view);
  intent.setdataandtype(uri .fromfile(new file(path)), "image/png");
  startactivity(intent);

对于图片上边的不适用索引格式会出错。

intent intent = new intent();
intent.setaction(android .content.intent.action_view);
file file = new file("/sdcard/test.mp4");
intent.setdataandtype(uri .fromfile(file), "video/*");
startactivity(intent);
intent intent = new intent();
intent.setaction(android .content.intent.action_view);
file file = new file("/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：

<activity
 android :name=".artistactivity"
 android :label="artist"
 android :launchmode="singletop">
</activity>

intent i = new intent();
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：

bitmap mycoolbitmap = ... ;
   int w = mycoolbitmap.getwidth(), h = mycoolbitmap.getheight();
   bitmap rounder = bitmap.createbitmap(w,h,bitmap.config.argb_8888);
   canvas canvas = new canvas(rounder);
   paint xferpaint = new paint(paint.anti_alias_flag);
   xferpaint.setcolor(color.red);
   canvas.drawroundrect(new rectf(0,0,w,h), 20.0f, 20.0f, xferpaint);
   xferpaint.setxfermode(new porterduffxfermode(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

notification notification = new notification (icon, tickertext, when);
notification .number = 4;

11.背景渐变：

首先建立文件drawable/shape.xml

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android ="http://schemas.android .com/apk/res/android " android :shape="rectangle">
  <gradient android :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

<?xml version="1.0" encoding="utf-8"?>
<resources>
<style name="newtheme" parent="android :theme">
<item name="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:

<activity android :name=".shapedemo" android :theme="@style/newtheme">

该方法同样适用于控件

<?php xml version="1.0" ?>
?
<response>
<error>1</error>
<message>invalid url.</message>
</response>

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

public class myapplication extends application{
  private string thing = null;
  public string getthing(){
   return thing;
  }
  public void setthing( string thing ){
   this.thing = thing;
  }
}
public class myactivity extends activity {
   private myapplication app;
   public void oncreate(bundle savedinstancestate) {
     super.oncreate(savedinstancestate);
     app = ((myapplication)getapplication());
     string thing = app.getthing();
   }
}

更多关于android相关内容感兴趣的读者可查看本站专题：《android开发入门与进阶教程》、《android视图view技巧总结》、《android布局layout技巧总结》、《android调试技巧与常见问题解决方法汇总》、《android多媒体操作技巧汇总(音频,视频,录音等)》、《android基本组件用法总结》及《android控件用法总结》

希望本文所述对大家android程序设计有所帮助。