Android 自己定义View须要重写ondraw()等方法

Android  自己定义View须要重写ondraw()等方法。这篇博客给大家说说自己定义View的写法，须要我们继承View，然后重写一些

方法，方法多多，看你须要什么方法

首先写一个自己定义的View 继承View

package com.example.engineerjspview;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.view.MotionEvent;
/**
 * 自己定义 EngineerJspView
 * @author Engineer-Jsp
 * @date 2014.10.28
 * */
import android.view.View;
public class EngineerJspView extends View{
	public float E_X = 188;
    public float E_Y = 188;
    Paint paint = new Paint(); 

	public EngineerJspView(Context context) {
		super(context);
	}
	public EngineerJspView(Context context, AttributeSet set){
		super(context, set);
	}
	@Override
	protected void onDraw(Canvas canvas) {
		super.onDraw(canvas);
		paint.setColor(Color.RED);
        canvas.drawCircle(E_X, E_Y, 88, paint);
	}
	@Override
	public boolean onTouchEvent(MotionEvent event) {
		 E_X = event.getX();
	     E_X = event.getY();
	        invalidate();
		return false;
	}
	@Override
	protected void onAnimationStart() {
		super.onAnimationStart();
	}
	@Override
	protected void onAnimationEnd() {
		super.onAnimationEnd();
	}

}

布局文件：

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity" >

    <com.example.engineerjspview.EngineerJspView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_alignParentBottom="true"
        android:layout_centerHorizontal="true" />

</RelativeLayout>

主活动：

package com.example.engineerjspview;
/**
 * 自己定义 EngineerJspView
 * @author Engineer-Jsp
 * @date 2014.10.28
 * */
import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.view.View;

public class MainActivity extends Activity {

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
	}

}

效果：

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自己定义View看你需求而定，并不仅仅是绘图形而已。我这里仅仅是说明下自己定义View须要重写的方法~~