java - 有大神能帮忙补充下代码吗(Android的Canvas和Paint的使用，和文件保存，手势识别)？

问题描述

研究了好久 都写不好 。。。

package com.li.zhuoyuan.designmodel;import android.content.Context;import android.os.Build;import android.util.Log;import android.view.MotionEvent;import android.view.ScaleGestureDetector;public abstract class GestureDetector { private static final String TAG = 'VersionedGestureDetector'; OnGestureListener mListener; public static GestureDetector newInstance(Context context, OnGestureListener listener) {final int sdkVersion = Integer.parseInt(Build.VERSION.SDK);GestureDetector detector = null;if (sdkVersion < Build.VERSION_CODES.ECLAIR) { detector = new CupcakeDetector();} else if (sdkVersion < Build.VERSION_CODES.FROYO) { detector = new EclairDetector();} else { detector = new FroyoDetector(context);}Log.d(TAG, 'Created new ' + detector.getClass());detector.mListener = listener;return detector; } public abstract boolean onTouchEvent(MotionEvent ev); public interface OnGestureListener {public void onDrag(float dx, float dy);public void onScale(float scaleFactor); } private static class CupcakeDetector extends GestureDetector {float mLastTouchX;float mLastTouchY;float getActiveX(MotionEvent ev) { return ev.getX();}float getActiveY(MotionEvent ev) { return ev.getY();}boolean shouldDrag() { return true;}@Overridepublic boolean onTouchEvent(MotionEvent ev) { switch (ev.getAction()) {case MotionEvent.ACTION_DOWN: { mLastTouchX = getActiveX(ev); mLastTouchY = getActiveY(ev); break;}case MotionEvent.ACTION_MOVE: { final float x = getActiveX(ev); final float y = getActiveY(ev); if (shouldDrag()) {mListener.onDrag(x - mLastTouchX, y - mLastTouchY); } mLastTouchX = x; mLastTouchY = y; break;} } return true;} } private static class EclairDetector extends CupcakeDetector {private static final int INVALID_POINTER_ID = -1;private int mActivePointerId = INVALID_POINTER_ID;private int mActivePointerIndex = 0;@Overridefloat getActiveX(MotionEvent ev) { return ev.getX(mActivePointerIndex);}@Overridefloat getActiveY(MotionEvent ev) { return ev.getY(mActivePointerIndex);}@Overridepublic boolean onTouchEvent(MotionEvent ev) { final int action = ev.getAction(); //No.1 //开始写代码，请结合所有代码在这里实现，计算手指在屏幕上移动的位置。从而方便其他调用这个类的地方更新屏幕上小机器人的位置。小机器人跟随手指移动。 switch (action & MotionEvent.ACTION_MASK) {case MotionEvent.ACTION_DOWN: mLastTouchX = ev.getX(); mLastTouchY = ev.getY(); break;case MotionEvent.ACTION_MOVE: mLastTouchX = ev.getX(); mLastTouchY = ev.getY(); } mActivePointerIndex = 0; //end_code return super.onTouchEvent(ev);} } private static class FroyoDetector extends EclairDetector {private ScaleGestureDetector mDetector;public FroyoDetector(Context context) { mDetector = new ScaleGestureDetector(context, new ScaleGestureDetector.SimpleOnScaleGestureListener() {@Overridepublic boolean onScale(ScaleGestureDetector detector) { mListener.onScale(detector.getScaleFactor()); return true;} });}@Overrideboolean shouldDrag() { return !mDetector.isInProgress();}@Overridepublic boolean onTouchEvent(MotionEvent ev) { mDetector.onTouchEvent(ev); return super.onTouchEvent(ev);} }}

package com.li.zhuoyuan.designmodel;import android.graphics.Bitmap;import android.graphics.Canvas;import android.graphics.Color;import android.graphics.Paint;import android.os.Bundle;import android.support.v7.app.AppCompatActivity;import android.view.MotionEvent;import android.view.View;import android.widget.Button;import android.widget.ImageView;import android.widget.Toast;import java.io.File;public class MainActivity extends AppCompatActivity { private Button button_save, button_resume; private ImageView iv_canvas; private Bitmap baseBitmap; private Canvas canvas; /*声明画笔*/ private Paint mPaint; /*手势监听器*/ private View.OnTouchListener onTouchListener = new View.OnTouchListener() {/*表示手指在屏幕上X轴Y轴的坐标点*/float startX;float startY;@Overridepublic boolean onTouch(View v, MotionEvent event) { switch (event.getAction()) {case MotionEvent.ACTION_DOWN: //No.1 //开始写代码，请用代码实现初始化Bitmap对象、定义画布颜色（请定义为白色）、记录用户手指在屏幕上的触摸点坐标 将坐标存入到startX和startY变量中。 Bitmap bitmap = Bitmap.createBitmap(iv_canvas.getWidth(), iv_canvas.getHeight(), Bitmap.Config.ARGB_8888); mPaint.setColor(Color.WHITE); startX = iv_canvas.getX(); startX = iv_canvas.getY(); //end_code break;case MotionEvent.ACTION_MOVE: //No.2 //开始写代码，根据手指在屏幕滑动的轨迹实现绘制轨迹的线条，并更新手指在屏幕上的坐标点（startX和startY变量），将绘制好的图像展示在ImageView中。 float stopX = iv_canvas.getX(); float stopY = iv_canvas.getY(); //end_code break;case MotionEvent.ACTION_UP: break;default: break; } return true;} }; @Override protected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);/*初始化画笔 设置画笔的宽度和颜色*/mPaint = new Paint();mPaint.setStrokeWidth(5);mPaint.setColor(Color.RED);iv_canvas = (ImageView) findViewById(R.id.iv_canvas);button_save = (Button) findViewById(R.id.button_save);button_resume = (Button) findViewById(R.id.button_resume);/*保存按钮的监听器*/button_save.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) {saveBitmap(); }});/*清除按钮的监听器*/button_resume.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) {resumeCanvas(); }});iv_canvas.setOnTouchListener(onTouchListener); } /*保存图片的方法*/ protected void saveBitmap() {try { /*以png的格式保存的手机内存中*/ //No.3 //开始写代码，请在这里实现文件存储的方法，将手指在屏幕上涂鸦的图形以PNG图片的形式保存到SD卡中；并发送广播进行扫描SD卡。 File file //end_code} catch (Exception e) { Toast.makeText(MainActivity.this, '保存图片失败', 0).show(); e.printStackTrace();} } /*清除画布的方法*/ protected void resumeCanvas() {if (baseBitmap != null) { baseBitmap = Bitmap.createBitmap(iv_canvas.getWidth(), iv_canvas.getHeight(), Bitmap.Config.ARGB_8888); canvas = new Canvas(baseBitmap); canvas.drawColor(Color.WHITE); iv_canvas.setImageBitmap(baseBitmap); Toast.makeText(MainActivity.this, '清除画板成功，可以重新开始绘图', 0).show();} }}

请输入代码

问题解答

直接说要做个什么功能比较好，这样估计没人回去帮你填代码

能把你的工资分我一份吗？