自定义View（板块随手指移动）

最新推荐文章于 2024-05-05 09:13:20 发布

Revival_Liang

最新推荐文章于 2024-05-05 09:13:20 发布

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分类专栏： Android

本文链接：https://blog.youkuaiyun.com/Revival_Liang/article/details/51542932

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本文介绍了一个具体的Android自定义View实现案例，通过触摸事件改变View的位置，并实现了简单的状态管理。文章详细展示了如何创建自定义View类，处理触摸事件，以及如何通过静态变量控制View的状态。

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package com.example.k.myapplication;

/**
 * Created by k on 2016/5/30.
 */
public class demo {
    static boolean b = false;
    static int a = 0;

    public static void startBoolean() {
        b = true;
    }
    public static void closeBoolean(){
        b = false;
    }
}

================================================================

package com.example.k.myapplication;

import android.graphics.Color;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.MotionEvent;

public class MainActivity extends AppCompatActivity {
MyView my;
    float value;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        my = (MyView)findViewById(R.id.my);
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        if (event.getAction() == MotionEvent.ACTION_UP) {
            demo.closeBoolean();
        }
        if (event.getAction() == MotionEvent.ACTION_DOWN) {// 按下即可触
            Log.i("ok","主");
            value = event.getY();
        }
        my.method((int)event.getX(),(int)(event.getY()-value));
        return super.onTouchEvent(event);
    }
}
================================================================================
package com.example.k.myapplication;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.util.Log;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewGroup;
import android.view.WindowManager;
import android.widget.RelativeLayout;

/**
 * Created by k on 2016/5/30.
 */
public class MyView extends View {
    int value = 0,value1=0;
    WindowManager wm = (WindowManager) getContext()
            .getSystemService(Context.WINDOW_SERVICE);

    int width = wm.getDefaultDisplay().getWidth();
    int height = wm.getDefaultDisplay().getHeight();
     int X;
    Context context;
   int Y;
    int a,c=0;
    public void method(int x,int y){
        value = getTop();
        Log.i("ok","y=======>"+y);
        if(demo.b) {
            if(value1 + y>0&&value1+200 + y<1280-160) {
                layout(getLeft(), value1 + y, getRight(), value1+200 + y);
            }
        }
    }
    private static final int DEFAULT_VIEW_WIDTH = 100;
    private static final int DEFAULT_VIEW_HEIGHT = 100;
    public MyView(Context context) {
        super(context);
    }
    public MyView(Context context, AttributeSet attrs) {
        super(context, attrs);
        this.context = context;
    }
    //测量自定义View的宽和高
    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMesureSpec) {
        int width  = measureDimension(DEFAULT_VIEW_WIDTH, widthMeasureSpec);
        int height = measureDimension(DEFAULT_VIEW_HEIGHT, heightMesureSpec);
        setMeasuredDimension(width, height);
    }
    protected int measureDimension( int defaultSize, int measureSpec ) {
        int result = defaultSize;
        int specMode = MeasureSpec.getMode(measureSpec);
        int specSize = MeasureSpec.getSize(measureSpec);
        //当子控件被width或者height被设置为确定值时就会被激活
        if (specMode == MeasureSpec.EXACTLY) {
            result = specSize; //建议：result直接使用确定值
            }
        //当子控件被设置为wrap_content时，就会进入此判断
        else if (specMode == MeasureSpec.AT_MOST) {
            result = Math.max(defaultSize, specSize); //建议：result不能大于specSize
            }
        //UNSPECIFIED,没有任何限制，所以可以设置任何大小
        //多半出现在自定义的父控件的情况下，期望由自控件自行决定大小
        else {
            result = defaultSize;
            }
        return result;
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        Paint paint = new Paint();
        paint.setColor(Color.YELLOW);
        //使view里面的正方形居中
        //canvas.drawRect(getWidth()/2-20,getHeight()/2-20,getWidth()/2+20,getHeight()/2+20,paint);
        //使正方形居中且靠右
        canvas.drawRect(0,getHeight()/2-20,40,getHeight()/2+20,paint);
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        demo.startBoolean();
        value1 = value;
        return super.onTouchEvent(event);
    }
}