android 用到的技巧集

1.Drawable的使用

 

 

android.graphics.drawable

 

Most often you will deal with Drawable as the type of resource retrieved for drawing things to the screen; the Drawable class provides a generic API for dealing with an underlying visual resource that may take a variety of forms.

 

最经常会处理Drawable作为类型的资源回收绘制到屏幕上的东西; Drawable类提供了一个通用的API来处理一个基本的视觉资源，可以采取多种形式。（讲的有点抽象）讲白点就是获取res下的参数

 

例：改变TextView文字颜色-引用Drawable颜色常熟及背景色

    values下的color.xml

 

<?xml version="1.0" encoding="utf-8" ?>
 <resources>
 <drawable name="darkgray">#808080FF</drawable>
 <drawable name="white">#FFFFFFFF</drawable>
 </resources>

    对文本框的背景色进行设置

Resources resources = getBaseContext().getResources();
Drawable HippoDrawable = resources.getDrawable(R.drawable.white);
mTextView01.setBackgroundDrawable(HippoDrawable);

 

2.获取手机屏幕大小

 

DisplayMetrics  dm = new DisplayMetrics();

getWindowManager().getDefaultDisplay().getMetrics(dm);

Stirng width = dm.widthPixels;

Stirng heiht = dm.heightPixels;

 
3.Android style 机制

仅仅是加了一个Style. 一个Style就能够实现控件的显示效果样式么?Android的Style机制真的很强大.
例:

 

<?xml version="1.0" encoding="utf-8" ?>
- <resources>
- <style name="DavidStyleText1">
  <item name="android:textSize">18sp</item>
  <item name="android:textColor">#EC9237</item>
  </style>
- <style name="DavidStyleText2">
  <item name="android:textSize">14sp</item>
  <item name="android:textColor">#FF7F7C</item>
  <item name="android:fromAlpha">0.0</item>
  <item name="android:toAlpha">0.0</item>
  </style>
  </resources>

 

<?xml version="1.0" encoding="utf-8" ?>
- <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:background="@drawable/white" android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent">
- <!--  应用模式1的TextView
  -->
  <TextView style="@style/DavidStyleText1" android:layout_width="fill_parent" android:layout_height="wrap_content" android:gravity="center_vertical|center_horizontal" android:text="@string/str_text_view1" />
- <!--  应用模式2的TextView
  -->
  <TextView style="@style/DavidStyleText2" android:layout_width="fill_parent" android:layout_height="wrap_content" android:gravity="center_vertical|center_horizontal" android:text="@string/str_text_view2" />
  </LinearLayout>