code perfect

app/src/main/java/com/mxdl/CaptureViewActivity.java

@@ -6,10 +6,11 @@ import android.os.Bundle;
 
 import com.mxdl.customview.R;
 import com.mxdl.customview.view.CaptureView;
+import com.mxdl.customview.view.CenterCaptureView;
 
 public class CaptureViewActivity extends AppCompatActivity {
 
-    private CaptureView mCaptureView;
+    private CenterCaptureView mCaptureView;
 
     @SuppressLint("WrongViewCast")
     @Override
@@ -17,6 +18,6 @@ public class CaptureViewActivity extends AppCompatActivity {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_capture_view);
         mCaptureView = findViewById(R.id.view_cpature);
-        mCaptureView.initCaptureFrame();
+        //mCaptureView.initCaptureFrame();
     }
 }

app/src/main/java/com/mxdl/customview/view/CenterCaptureView.java

+package com.mxdl.customview.view;
+
+import android.content.Context;
+import android.graphics.Canvas;
+import android.graphics.Color;
+import android.graphics.Paint;
+import android.graphics.Path;
+import android.graphics.Rect;
+import android.graphics.RectF;
+import android.graphics.drawable.Drawable;
+import android.os.Build;
+import android.support.annotation.RequiresApi;
+import android.util.AttributeSet;
+import android.view.MotionEvent;
+import android.view.View;
+
+import com.mxdl.customview.R;
+
+/**
+ * Description: <CenterCaptureView><br>
+ * Author:      mxdl<br>
+ * Date:        2019/10/12<br>
+ * Version:     V1.0.0<br>
+ * Update:     <br>
+ */
+public class CenterCaptureView extends View {
+    private int mWidth;
+    private Rect mScreenRect = new Rect();
+    private Rect mCaptureRect = new Rect();
+    private Paint mBorderPaint = new Paint();
+    private Path mCapturePath = new Path();
+    private Paint mAreaPaint = new Paint();
+    private Drawable mAnchorDrawable;
+    private int mHalfAnchorWidth;
+    private int mLastX;
+    private int mLastY;
+    private int mHitCorner;
+
+    public CenterCaptureView(Context context) {
+        super(context);
+        initView();
+    }
+
+    public CenterCaptureView(Context context, AttributeSet attrs) {
+        super(context, attrs);
+        initView();
+    }
+
+    public CenterCaptureView(Context context, AttributeSet attrs, int defStyleAttr) {
+        super(context, attrs, defStyleAttr);
+        initView();
+    }
+
+    @RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)
+    public CenterCaptureView(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
+        super(context, attrs, defStyleAttr, defStyleRes);
+        initView();
+    }
+
+    public void initView() {
+        mWidth = (int) (getResources().getDisplayMetrics().density * 216 + 0.5f);
+        mBorderPaint.setStrokeWidth(getResources().getDisplayMetrics().density * 2);
+        mBorderPaint.setStyle(Paint.Style.STROKE);
+        mBorderPaint.setAntiAlias(true);
+        mBorderPaint.setColor(Color.parseColor("#1E88E5"));
+
+        mAreaPaint.setStyle(Paint.Style.FILL_AND_STROKE);
+        mAreaPaint.setColor(Color.parseColor("#1E88E5"));
+        mAreaPaint.setAlpha(20);
+
+        mAnchorDrawable = getResources().getDrawable(R.mipmap.ic_edit_fence_dragger);
+        mHalfAnchorWidth = mAnchorDrawable.getIntrinsicWidth() / 2;
+    }
+
+    @Override
+    protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
+        super.onLayout(changed, left, top, right, bottom);
+        mScreenRect.set(left, top, right, bottom);
+        int captureLeft = (right - mWidth) / 2;
+        int captureTop = (bottom - mWidth) / 2;
+        int captureRight = captureLeft + mWidth;
+        int captureBottom = captureTop + mWidth;
+        mCaptureRect.set(captureLeft, captureTop, captureRight, captureBottom);
+    }
+
+    @Override
+    protected void onDraw(Canvas canvas) {
+        super.onDraw(canvas);
+        mCapturePath.reset();
+        mCapturePath.addRect(new RectF(mCaptureRect), Path.Direction.CW);
+        //画矩形区域
+        canvas.drawRect(mCaptureRect, mAreaPaint);
+        //画矩形边框
+        canvas.drawPath(mCapturePath, mBorderPaint);
+
+        //画左上锚点
+        
+        mAnchorDrawable.setBounds(mCaptureRect.left - mHalfAnchorWidth, mCaptureRect.top - mHalfAnchorWidth, mCaptureRect.left + mHalfAnchorWidth, mCaptureRect.top + mHalfAnchorWidth);
+        mAnchorDrawable.draw(canvas);
+
+        //画右上锚点
+        mAnchorDrawable.setBounds(mCaptureRect.right - mHalfAnchorWidth, mCaptureRect.top - mHalfAnchorWidth, mCaptureRect.right + mHalfAnchorWidth, mCaptureRect.top + mHalfAnchorWidth);
+        mAnchorDrawable.draw(canvas);
+
+        //画右下锚点
+        mAnchorDrawable.setBounds(mCaptureRect.right - mHalfAnchorWidth, mCaptureRect.bottom - mHalfAnchorWidth, mCaptureRect.right + mHalfAnchorWidth, mCaptureRect.bottom + mHalfAnchorWidth);
+        mAnchorDrawable.draw(canvas);
+
+        //画左下锚点
+        mAnchorDrawable.setBounds(mCaptureRect.left - mHalfAnchorWidth, mCaptureRect.bottom - mHalfAnchorWidth, mCaptureRect.left + mHalfAnchorWidth, mCaptureRect.bottom + mHalfAnchorWidth);
+        mAnchorDrawable.draw(canvas);
+
+    }
+
+    @Override
+    public boolean onTouchEvent(MotionEvent event) {
+        int x = (int) event.getX();
+        int y = (int) event.getY();
+        
+        switch (event.getAction()){
+            case MotionEvent.ACTION_DOWN:
+                mHitCorner = getHitCorner(x, y);
+                //如果没有点击在锚点上，则直接返回false
+                if(mHitCorner == 0){
+                    return false;
+                }
+                break;
+            case MotionEvent.ACTION_UP:
+                mHitCorner = 0;
+                break;
+            case MotionEvent.ACTION_MOVE:
+                if(mHitCorner == 0){
+                    return false;
+                }
+                int dx = x - mLastX;
+                int dy = y - mLastY;
+                if(mHitCorner == 7){
+                    mCaptureRect.left += dx;
+                    mCaptureRect.top += dy;
+                    mCaptureRect.right -= dx;
+                    mCaptureRect.bottom -= dy;
+                }else if(mHitCorner == 9){
+                   mCaptureRect.left -= dx;
+                    mCaptureRect.top += dy;
+                    mCaptureRect.right += dx;
+                    mCaptureRect.bottom -= dy;
+                }else if(mHitCorner == 3){
+                    mCaptureRect.left -= dx;
+                    mCaptureRect.top -= dy;
+                    mCaptureRect.right += dx;
+                    mCaptureRect.bottom += dy;
+                }else if(mHitCorner == 1){
+                    mCaptureRect.left += dx;
+                    mCaptureRect.top -= dy;
+                    mCaptureRect.right -= dx;
+                    mCaptureRect.bottom += dy;
+                }
+                break;
+        }
+        mLastX = x;
+        mLastY = y;
+        invalidate();
+        return true;
+    }
+    public int getHitCorner(float x, float y) {
+        int result = 0;
+        if (y > mCaptureRect.top - mHalfAnchorWidth && y < mCaptureRect.top + mHalfAnchorWidth) {
+            if (x > mCaptureRect.left - mHalfAnchorWidth && x < mCaptureRect.left + mHalfAnchorWidth) {
+                result = 7;
+            } else if (x > mCaptureRect.right - mHalfAnchorWidth && x < mCaptureRect.right + mHalfAnchorWidth) {
+                result = 9;
+            }
+        } else if (y > mCaptureRect.bottom - mHalfAnchorWidth && y < mCaptureRect.bottom + mHalfAnchorWidth) {
+            if (x > mCaptureRect.left - mHalfAnchorWidth && x < mCaptureRect.left + mHalfAnchorWidth) {
+                result = 1;
+            } else if (x > mCaptureRect.right - mHalfAnchorWidth && x < mCaptureRect.right + mHalfAnchorWidth) {
+                result = 3;
+            }
+        }
+        return result;
+    }
+}

app/src/main/res/layout/activity_capture_view.xml

@@ -3,7 +3,8 @@
                 android:layout_width="match_parent"
                 android:layout_height="match_parent">
 
-    <com.mxdl.customview.view.CaptureView
+    <com.mxdl.customview.view.CenterCaptureView
+
         android:id="@+id/view_cpature"
         android:layout_width="match_parent"
         android:layout_height="match_parent"