這篇文章主要講解了Android自定義View實(shí)現(xiàn)可拖拽縮放的矩形框的方法,內(nèi)容清晰明了,對(duì)此有興趣的小伙伴可以學(xué)習(xí)一下,相信大家閱讀完之后會(huì)有幫助。
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在開(kāi)發(fā)項(xiàng)目中,需要一個(gè)矩形框來(lái)實(shí)現(xiàn)截屏功能,并且還需要可以任意拖拽和縮放,這就需要自定義View來(lái)實(shí)現(xiàn)了,具體功能如下:
1.自定義View
package com.xinrui.screenshot.view; import android.content.Context; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.Paint; import android.graphics.RectF; import android.support.annotation.Nullable; import android.util.AttributeSet; import android.util.Log; import android.util.TypedValue; import android.view.MotionEvent; import android.view.View; public class CropRectView extends View { // 繪制 損害框和損害名稱(chēng) private Paint mPaint; private RectF mRectF; // 邊緣字體 // private BorderedText mBorderedText; // 標(biāo)題 或 名字 private String mTitle; // 概率 private float mConfidence; // 矩形框 corner 的角度:直角、圓角 private int mCornerAngle; //直角 默認(rèn) public static final int RIGHT_CORNER = 0; //圓角 public static final int ROUND_CORNER = 1; // Remove Rect private int MODE; private static final int MODE_OUTSIDE = 0x000000aa;/*170*/ private static final int MODE_INSIDE = 0x000000bb;/*187*/ private static final int MODE_POINT = 0X000000cc;/*204*/ private static final int MODE_ILLEGAL = 0X000000dd;/*221*/ private float startX;/*start X location*/ private float startY;/*start Y location*/ private float endX;/*end X location*/ private float endY;/*end Y location*/ private float currentX;/*X coordinate values while finger press*/ private float currentY;/*Y coordinate values while finger press*/ private float memoryX;/*the last time the coordinate values of X*/ private float memoryY;/*the last time the coordinate values of Y*/ private float mCoverWidth;/*width of selection box*/ private float mCoverHeight;/*height of selection box*/ private static final int ACCURACY = 100;/*touch accuracy*/ private int pointPosition;/*vertex of a rectangle*/ private static final float minWidth = 100.0f;/*the minimum width of the rectangle*/ private static final float minHeight = 200.0f;/*the minimum height of the rectangle*/ private onLocationListener mLocationListener;/*listen to the Rect */ private static final float EDGE_WIDTH = 1.8f; public MoveAndCropRectView(Context context) { this(context, null); } public MoveAndCropRectView(Context context, @Nullable AttributeSet attrs) { this(context, attrs, 0); } public MoveAndCropRectView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) { super(context, attrs, defStyleAttr); initDatas(context); } private void initDatas(Context context) { mPaint = new Paint(); mRectF = new RectF(); //畫(huà)筆設(shè)置空心 mPaint.setStyle(Paint.Style.STROKE); mPaint.setColor(Color.WHITE); mPaint.setStrokeWidth(2); mPaint.setAntiAlias(true); // float textSizePx = TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, // 18.0f, context.getResources().getDisplayMetrics()); // mBorderedText = new BorderedText(textSizePx); currentX = 0; currentY = 0; } private boolean firstDraw = true; @Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); // switch (mCornerAngle) { // case RIGHT_CORNER:// 繪制 損害框(直角矩形框) // drawRect(canvas); // break; // case ROUND_CORNER:// 繪制 損害框(圓角矩形框) // drawRoundRect(canvas); // break; // } if (firstDraw) { firstDraw = false; startX = mRectF.left; startY = mRectF.top; endX = mRectF.right; endY = mRectF.bottom; mCoverWidth = mRectF.width(); mCoverHeight = mRectF.height(); } if (mLocationListener != null) { mLocationListener.locationRect(startX, startY, endX, endY); } // LogUtils.d("onDraw -- startX: " + startX); canvas.drawLine(startX - EDGE_WIDTH, startY - EDGE_WIDTH, endX + EDGE_WIDTH, startY - EDGE_WIDTH, mPaint);/*top 上邊框-*/ canvas.drawLine(startX - EDGE_WIDTH, endY + EDGE_WIDTH, endX + EDGE_WIDTH, endY + EDGE_WIDTH, mPaint);/*bottom -*/ canvas.drawLine(startX - EDGE_WIDTH, startY - EDGE_WIDTH, startX - EDGE_WIDTH, endY + EDGE_WIDTH, mPaint);/*left |*/ canvas.drawLine(endX + EDGE_WIDTH, startY - EDGE_WIDTH, endX + EDGE_WIDTH, endY + EDGE_WIDTH, mPaint);/*right |*/ // 繪制名稱(chēng) 和 概率 // final String labelString = // !TextUtils.isEmpty(mTitle) // ? String.format("%s %.2f", mTitle, (100 * mConfidence)) // : String.format("%.2f", (100 * mConfidence)); // // // 在 直角矩形框 上寫(xiě)字 // mBorderedText.drawText(canvas, // startX, // startY, labelString + "%", // mPaint); } @SuppressWarnings("NullableProblems") @Override public boolean onTouchEvent(MotionEvent event) { switch (event.getAction()) { case MotionEvent.ACTION_DOWN: memoryX = event.getX(); memoryY = event.getY(); checkMode(memoryX, memoryY); break; case MotionEvent.ACTION_MOVE: { currentX = event.getX(); currentY = event.getY(); switch (MODE) { case MODE_ILLEGAL: recoverFromIllegal(currentX, currentY); postInvalidate(); break; case MODE_OUTSIDE: //do nothing; break; case MODE_INSIDE://拖動(dòng) moveByTouch(currentX, currentY); postInvalidate(); break; default: /*MODE_POINT*/ moveByPoint(currentX, currentY); postInvalidate(); break; } } break; case MotionEvent.ACTION_UP: // mPaint.setColor(getContext().getResources().getColor(R.color.orange)); postInvalidate(); break; default: break; } return true; } /*點(diǎn)擊頂點(diǎn)附近時(shí)的縮放處理*/ @SuppressWarnings("SuspiciousNameCombination") private void moveByPoint(float bx, float by) { // LogUtils.d("moveByPoint"); switch (pointPosition) { case 0:/*left-up*/ mCoverWidth = Math.abs(endX - bx); mCoverHeight = Math.abs(endY - by); //noinspection SuspiciousNameCombination if (!checkLegalRect(mCoverWidth, mCoverHeight)) { MODE = MODE_ILLEGAL; } else { refreshLocation(bx, by, endX, endY); } break; case 1:/*right-up*/ mCoverWidth = Math.abs(bx - startX); mCoverHeight = Math.abs(endY - by); if (!checkLegalRect(mCoverWidth, mCoverHeight)) { MODE = MODE_ILLEGAL; } else { refreshLocation(startX, by, bx, endY); } break; case 2:/*left-down*/ mCoverWidth = Math.abs(endX - bx); mCoverHeight = Math.abs(by - startY); if (!checkLegalRect(mCoverWidth, mCoverHeight)) { MODE = MODE_ILLEGAL; } else { refreshLocation(bx, startY, endX, by); } break; case 3:/*right-down*/ mCoverWidth = Math.abs(bx - startX); mCoverHeight = Math.abs(by - startY); if (!checkLegalRect(mCoverWidth, mCoverHeight)) { MODE = MODE_ILLEGAL; } else { refreshLocation(startX, startY, bx, by); } break; default: break; } } /*刷新矩形的坐標(biāo)*/ private void refreshLocation(float isx, float isy, float iex, float iey) { this.startX = isx; this.startY = isy; this.endX = iex; this.endY = iey; mCoverWidth = endX - startX; mCoverHeight = endY - startY; } /*檢測(cè)矩形是否達(dá)到最小值*/ private boolean checkLegalRect(float cHeight, float cWidth) { return (cHeight > minHeight && cWidth > minWidth); } /*從非法狀態(tài)恢復(fù),這里處理的是達(dá)到最小值后能拉伸放大*/ private void recoverFromIllegal(float rx, float ry) { if ((rx > startX && ry > startY) && (rx < endX && ry < endY)) { MODE = MODE_ILLEGAL; } else { MODE = MODE_POINT; } } /** * 判斷點(diǎn)在矩形的什么位置 * @param cx * @param cy */ private void checkMode(float cx, float cy) { if (cx > startX && cx < endX && cy > startY && cy < endY) { MODE = MODE_INSIDE;//矩形內(nèi)部 } else if (nearbyPoint(cx, cy) < 4) { MODE = MODE_POINT;//矩形點(diǎn)上 } else { MODE = MODE_OUTSIDE;//矩形外部 } } /*矩形隨手指移動(dòng)*/ private void moveByTouch(float mx, float my) {/*move center point*/ float dX = mx - memoryX; float dY = my - memoryY; startX += dX; startY += dY; if(startX<=0){ startX=0; } if(startY<=0){ startY=0; } endX = startX + mCoverWidth; endY = startY + mCoverHeight; if(endX>=1920){ endX=1920; startX=endX-mCoverWidth; } if(endY>=1080){ endY=1080; startY=endY-mCoverHeight; } memoryX = mx; memoryY = my; } /*判斷點(diǎn)(inX,inY)是否靠近矩形的4個(gè)頂點(diǎn)*/ private int nearbyPoint(float floatX, float floatY) { if ((Math.abs(startX - floatX) <= ACCURACY && (Math.abs(floatY - startY) <= ACCURACY))) {/*left-up angle*/ pointPosition = 0; return 0; } if ((Math.abs(endX - floatX) <= ACCURACY && (Math.abs(floatY - startY) <= ACCURACY))) {/*right-up angle*/ pointPosition = 1; return 1; } if ((Math.abs(startX - floatX) <= ACCURACY && (Math.abs(floatY - endY) <= ACCURACY))) {/*left-down angle*/ pointPosition = 2; return 2; } if ((Math.abs(endX - floatX) <= ACCURACY && (Math.abs(floatY - endY) <= ACCURACY))) {/*right-down angle*/ pointPosition = 3; return 3; } pointPosition = 100; return 100; } // 設(shè)置矩形框 public void setRectF(RectF rectf) { this.mRectF = rectf; } public void setTitle(String title) { mTitle = title; } public void setConfidence(float confidence) { mConfidence = confidence; } public void setCornerAngle(int cornerAngle) { this.mCornerAngle = cornerAngle; } // 繪制 損害框(直角矩形框) private void drawRect(Canvas canvas) { canvas.drawRect(mRectF, mPaint); // 繪制名稱(chēng) 和 概率 // final String labelString = // !TextUtils.isEmpty(mTitle) // ? String.format("%s %.2f", mTitle, (100 * mConfidence)) // : String.format("%.2f", (100 * mConfidence)); // 在 直角矩形框 上寫(xiě)字 // mBorderedText.drawText(canvas, // mRectF.left, // mRectF.top, labelString + "%", // mPaint); } // 繪制 損害框(圓角矩形框) private void drawRoundRect(Canvas canvas) { float cornerSize = Math.min(mRectF.width(), mRectF.height()) / 8.0f; canvas.drawRoundRect(mRectF, cornerSize, cornerSize, mPaint); // 繪制名稱(chēng) 和 概率 // final String labelString = // !TextUtils.isEmpty(mTitle) // ? String.format("%s %.2f", mTitle, (100 * mConfidence)) // : String.format("%.2f", (100 * mConfidence)); // 在 圓角矩形框 上寫(xiě)字 // mBorderedText.drawText(canvas, // mRectF.left + cornerSize, // mRectF.top, labelString + "%", // mPaint); } public void setLocationListener(onLocationListener mLocationListener) { this.mLocationListener = mLocationListener; } public interface onLocationListener { void locationRect(float startX, float startY, float endX, float endY); } }
2.Activity里的應(yīng)用
package com.xinrui.screenshot; import android.app.Activity; import android.graphics.RectF; import android.os.Bundle; import android.util.Log; import android.widget.RelativeLayout; import com.xinrui.screenshot.view.CropRectView; public class MainActivity extends Activity { private RelativeLayout main_area; CropRectView cropRectView; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); initview(); } private void initview(){ main_area = (RelativeLayout)findViewById(R.id.main_area); cropRectView = (CropRectView)findViewById(R.id.main_img); RectF rectF = new RectF(660, 240, 1260, 840); cropRectView.setRectF(rectF); cropRectView.setLocationListener(new CropRectView.onLocationListener() { @Override public void locationRect(float startX, float startY, float endX, float endY) { Log.e("MainActivity","[ startX:(" + startX + ")--startY:(" + startY + ")--endX:(" + endX + ")--endY:(" + endY + ") ]"); } }); } }
3.activity_main.xml
<?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/main_area" android:layout_width="match_parent" android:layout_height="match_parent"> <com.xinrui.screenshot.view.CropRectView android:id="@+id/main_img" android:layout_centerInParent="true" android:layout_width="match_parent" android:layout_height="match_parent"/> </RelativeLayout>
看完上述內(nèi)容,是不是對(duì)Android自定義View實(shí)現(xiàn)可拖拽縮放的矩形框的方法有進(jìn)一步的了解,如果還想學(xué)習(xí)更多內(nèi)容,歡迎關(guān)注創(chuàng)新互聯(lián)行業(yè)資訊頻道。
網(wǎng)站題目:Android自定義View實(shí)現(xiàn)可拖拽縮放的矩形框的方法
標(biāo)題路徑:http://aaarwkj.com/article18/iihpdp.html
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