Android 自定义View

Android 自定义View为MyCustomView。在MyCustomView画了一个Rect，

颜色为Green，和一个为红色的文字。

public class MyCustomView extends View{

	 private Paint mPaint;  
     private Context mContext;  
     private static final String mString = "Hello world!";  

	
	public MyCustomView(Context context) {
		super(context);
		// TODO Auto-generated constructor stub
	}
	
	public MyCustomView(Context context, AttributeSet attr) {
		super(context,attr);
		// TODO Auto-generated constructor stub
		
	}
	
	 @Override  
     protected void onDraw(Canvas canvas) {  
         // TODO Auto-generated method stub  
         super.onDraw(canvas);  
           
         mPaint = new Paint();  
         
         mPaint.setColor(Color.GREEN);
         mPaint.setStyle(Style.FILL);
         
         canvas.drawRect(new Rect(10, 10, 300, 500), mPaint);  
           
         mPaint.setColor(Color.RED);  
         canvas.drawText(mString, 50, 550, mPaint); 
	 }
}

 将自定义的View添加到activity_main的Layout中

<?xml version="1.0" encoding="utf-8"?>  
    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"  
        android:orientation="vertical"  
        android:layout_width="fill_parent"  
        android:layout_height="fill_parent"  
        >  
    <TextView    
        android:layout_width="fill_parent"   
        android:layout_height="wrap_content"   
        android:text="@string/hello_world"  
        />  
   <com.example.customview.MyCustomView 
       android:layout_width="fill_parent"
       android:layout_height="fill_parent"
       />
    </LinearLayout>

 参考

其中Layout中的<com.example.customview.MyCustomView />就是对该自定义控件的使用。

---

二、为MyCustomView添加自定义属性

在value文件夹下建attrs.xml文件。 定义了两个属性，分别为文本颜色和文本大小。

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <declare-styleable name="MyView">
        <attr name="textColor" format="color" />
        <attr name="textSize" format="dimension" />
    </declare-styleable>
</resources>

MyCustomView类更改如下

public class MyCustomView extends View {

	private Paint mPaint;
	private Context mContext;
	private static final String mString = "Hello world!";
	public MyCustomView(Context context) {
		super(context);
		mPaint = new Paint();
	}


	public MyCustomView(Context context, AttributeSet attr) {
		super(context, attr);
		mPaint = new Paint();
		TypedArray array = context.obtainStyledAttributes(attr, R.styleable.MyView);
		int textColor = array.getColor(R.styleable.MyView_textColor, 0XFFFFFFFF);
		float textSize = array.getDimension(R.styleable.MyView_textSize, 30);
		mPaint.setColor(textColor);
		mPaint.setTextSize(textSize);
		
		array.recycle(); //TypedArray通常最后调用 .recycle() 方法，为了保持以后使用该属性一致性！
		
	}

	@Override
	protected void onDraw(Canvas canvas) {

		// TODO Auto-generated method stub

		super.onDraw(canvas);
		mPaint.setStyle(Style.FILL);
		canvas.drawRect(new Rect(10, 10, 300, 500), mPaint);
		mPaint.setColor(Color.RED);
		canvas.drawText(mString, 50, 550, mPaint);
	}

}

Layout更改如下

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:test="http://schemas.android.com/apk/res/com.example.customviewdemo"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity" >

    <com.example.customviewdemo.MyCustomView
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        test:textColor="#00ff00"
        test:textSize="20sp" />

</RelativeLayout>

　　注意：1. xmlns:test=http://schemas.android.com/apk/res/com.example.customviewdemo  test是自定义的，名字随便取。com.example.customviewdemo 是包名。

　　　　　2. test:textColor="#00ff00" test:textSize="20sp" 这两个就是要调用的自定义属性。

　　效果如下图：