Android画一个随意拖动的圆形

import android.content.Context;import android.graphics.Bitmap;import android.graphics.BitmapFactory;import android.graphics.Canvas;import android.graphics.Color;import android.graphics.Matrix;import android.graphics.Paint;import android.graphics.PorterDuff;import android.graphics.PorterDuffXfermode;import android.graphics.Rect;import android.graphics.RectF;import android.graphics.Typeface;import android.view.MotionEvent;import android.view.View;/** * Created by songximing on 15/12/25. */public class DraggableView extends View {      /* (non-Javadoc)         * @see android.view.View#onDraw(android.graphics.Canvas)         */    protected float currentx = 0;// 拖拽控件的x坐标    protected float currenty = 0;// 拖拽控件的y坐标    private int r = 0;//拖拽球的半径    private boolean state = false;//判断控件是否应该获得焦点    private Paint paint = null;//画笔    private Paint paint1 = null;//画笔    private Paint paintLine = null;//画笔线    private Paint paintText = null;//画文字    private static int ALPHA_1 = 50;//画笔的透明度为半透明    private static int ALPHA_2 = 255;//画笔的透明度不透明    private float downX = 0f;//判断是否移动了x    private float downY = 0f;//判断是否移动了y    private Context context = null;//上下文    private DraggableView.ViewCallBack callBack = null;//回调    public DraggableView(Context context, DraggableView.ViewCallBack callBack) {        super(context);        this.context = context;        this.callBack = callBack;        initPaint();    }    @Override    protected void onDraw(Canvas canvas) {        super.onDraw(canvas);        drawView(canvas, 50, 11);    }    @Override    public boolean onTouchEvent(MotionEvent event) {        float x = event.getX();//获取点击的横坐标        float y = event.getY();//获取点击的纵坐标        //触摸事件的触发        switch (event.getAction()) {            case MotionEvent.ACTION_DOWN://触摸点击动作                downX = x;                downY = y;                if (!isOption(x, y)) {                    state = false;                    return false;                } else {                    paint.setAlpha(ALPHA_2);                    paint1.setAlpha(ALPHA_2);//设置画笔为半透明                    this.invalidate();                    state = true;                }                break;            case MotionEvent.ACTION_MOVE://触摸移动动作                if (state) {                    viewMove(x, y, event);                    this.invalidate();                }                break;            case MotionEvent.ACTION_UP://触摸离开动作                paint.setAlpha(ALPHA_1);//设置画笔为半透明                paint1.setAlpha(ALPHA_1);//设置画笔为半透明                this.invalidate();                if (downX == x && downY == y) {                    callBack.finishActivity(context);                }                break;        }        return true;    }    /**     * 画控件     *     * @param canvas 画板     * @param with   控件的宽度比例     * @param heigh  控件的高度比例     */    private void drawView(Canvas canvas, int with, int heigh) {//        if (getWidth() < getHeight()) {//            r = getWidth() / with;//        } else {//            r = getHeight() / heigh;//        }        r = with;        //如果是第一次画,画起始位置        if (currentx == 0 && currenty == 0) {            currentx = getWidth() - r;            currenty = getHeight() - 3 * r;            paint.setAlpha(ALPHA_1);            paint1.setAlpha(ALPHA_1);        }        //画一个圆形bitmap        // Bitmap bt1 = BitmapFactory.decodeResource(getResources(), R.mipmap.ww);        // Bitmap bt2 = zoomImg(bt1, 2 * r, 2 * r);        // Bitmap bt = toRoundBitmap(bt2);        // canvas.drawBitmap(bt, currentx - r, currenty - r, paint);        //可以改为图片资源        //用画笔画一个圆球(不使用字体)        canvas.drawCircle(currentx, currenty, r, paint1);        canvas.drawCircle(currentx, currenty, r - 5, paint);        int l = r / 4;        canvas.drawLine(currentx - l, currenty - l, currentx + l, currenty + l, paintLine);        canvas.drawLine(currentx - l, currenty + l, currentx + l, currenty - l, paintLine);        //用画笔画一个圆球（使用字体）        //canvas.drawCircle(currentx, currenty, r, paint1);        //canvas.drawCircle(currentx, currenty, r-5, paint);        //float bottom = paintText.getFontMetrics().bottom;        //float w = paintText.measureText("\uF00D");        //canvas.drawText("\uf00d", currentx - w / 2, currenty + 3 * bottom, paintText);    }    /**     * 初试化画笔     */    private void initPaint() {        paint = new Paint();        paint.setAntiAlias(true);        paint.setColor(Color.rgb(18, 26, 34));        paint1 = new Paint();        paint1.setAntiAlias(true);        paint1.setColor(Color.WHITE);        paintLine = new Paint();        paintLine.setColor(Color.WHITE);        paintLine.setStrokeWidth(5);        paintLine.setAntiAlias(true);        paintText = new Paint();        paintText = new Paint();        paintText.setColor(Color.WHITE);        Typeface tf = Typeface.createFromAsset(context.getAssets(), "fonts/FontAwesome.ttf");        paintText.setTextSize(50);        paintText.setTypeface(tf);    }    /**     * 设置滑动的效果     *     * @param x     点击的x坐标轴     * @param y     点击的y坐标轴     * @param event 控件的事件     */    private void viewMove(float x, float y, MotionEvent event) {        if (x <= r) {            currentx = r;        } else if (x >= getWidth() - r) {            currentx = getWidth() - r;        } else if (y <= r) {            currenty = r;        } else if (y >= getHeight() - r) {            currenty = getHeight() - r;        } else {            currentx = event.getX();            currenty = event.getY();        }    }    /**     * 判断是不是在控件可操作的范围之内     *     * @param x 点击的x坐标轴     * @param y 点击的y坐标轴     */    private boolean isOption(float x, float y) {        if (x > currentx - r && x < currentx + r && y < currenty + r & y > currenty - r)            return true;        else            return false;    }    /**     * 回调     */    public interface ViewCallBack {        public void finishActivity(Context context);    }    public Bitmap zoomImg(Bitmap bm, int newWidth, int newHeight) {        // 获得图片的宽高        int width = bm.getWidth();        int height = bm.getHeight();        // 计算缩放比例        float scaleWidth = ((float) newWidth) / width;        float scaleHeight = ((float) newHeight) / height;        // 取得想要缩放的matrix参数        Matrix matrix = new Matrix();        matrix.postScale(scaleWidth, scaleHeight);        // 得到新的图片   www.2cto.com        Bitmap newbm = Bitmap.createBitmap(bm, 0, 0, width, height, matrix, true);        return newbm;    }    /**     * 转换图片成圆形     *     * @param bitmap 传入Bitmap对象     * @return     */    public Bitmap toRoundBitmap(Bitmap bitmap) {        int width = bitmap.getWidth();        int height = bitmap.getHeight();        float roundPx;        float left, top, right, bottom, dst_left, dst_top, dst_right, dst_bottom;        if (width <= height) {            roundPx = width / 2;            top = 0;            bottom = width;            left = 0;            right = width;            height = width;            dst_left = 0;            dst_top = 0;            dst_right = width;            dst_bottom = width;        } else {            roundPx = height / 2;            float clip = (width - height) / 2;            left = clip;            right = width - clip;            top = 0;            bottom = height;            width = height;            dst_left = 0;            dst_top = 0;            dst_right = height;            dst_bottom = height;        }        Bitmap output = Bitmap.createBitmap(width,                height, Bitmap.Config.ARGB_8888);        Canvas canvas = new Canvas(output);        final int color = 0xff424242;        final Paint paint = new Paint();        final Rect src = new Rect((int) left, (int) top, (int) right, (int) bottom);        final Rect dst = new Rect((int) dst_left, (int) dst_top, (int) dst_right, (int) dst_bottom);        final RectF rectF = new RectF(dst_left, dst_top, dst_right, dst_bottom);        paint.setAntiAlias(true);        canvas.drawARGB(0, 0, 0, 0);        paint.setColor(color);        canvas.drawRoundRect(rectF, roundPx, roundPx, paint);        paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));        canvas.drawBitmap(bitmap, src, dst, paint);        return output;    }}

调用：

 1  2  3 import android.content.Context; 4 import android.content.Intent; 5 import android.support.v7.app.AppCompatActivity; 6 import android.os.Bundle; 7 import android.view.View; 8 import android.widget.RelativeLayout; 9 10 public class MainActivity extends AppCompatActivity {11 12     @Override13     protected void onCreate(Bundle savedInstanceState) {14         super.onCreate(savedInstanceState);15         RelativeLayout relativeLayout = new RelativeLayout(this);//(RelativeLayout) findViewById(R.id.rl);16         DraggableView draggableView  = new DraggableView(this,new DraggableView.ViewCallBack(){17 18             @Override19             public void finishActivity(Context context) {20                 Intent intent = new Intent(MainActivity.this,SecondActivity.class);21                 startActivity(intent);22                 overridePendingTransition(R.anim.slide_in, R.anim.no_anim);23             }24         });25         relativeLayout.addView(draggableView);26 27         setContentView(relativeLayout);28     }29 }

转载于:https://www.cnblogs.com/weifengzz/p/5194638.html

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