手写签名Demo

package com.activity; import android.app.Activity; import android.content.Context; import android.graphics.Bitmap; import android.graphics.Bitmap.Config; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.Paint; import android.graphics.Path; import android.os.Bundle; import android.view.MotionEvent; import android.view.View; import android.widget.Button; import android.widget.FrameLayout; import android.widget.ImageView; public class MainActivity extends Activity { private ImageView imageSign; private PaintView mView; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); imageSign = (ImageView) findViewById(R.id.iv_sign); FrameLayout frameLayout = (FrameLayout) findViewById(R.id.tablet_view); mView = new PaintView(this); frameLayout.addView(mView); mView.requestFocus(); Button btnClear = (Button) findViewById(R.id.tablet_clear); btnClear.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { mView.clear(); } }); Button btnOk = (Button) findViewById(R.id.tablet_ok); btnOk.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { Bitmap imageBitmap = mView.getCachebBitmap(); imageSign.setImageBitmap(imageBitmap); } }); } class PaintView extends View { private Paint paint; private Canvas cacheCanvas; private Bitmap cachebBitmap; private Path path; public Bitmap getCachebBitmap() { return cachebBitmap; } public PaintView(Context context) { super(context); init(); } private void init() { paint = new Paint(); paint.setAntiAlias(true); paint.setStrokeWidth(3); paint.setStyle(Paint.Style.STROKE); paint.setColor(Color.BLACK); path = new Path(); cachebBitmap = Bitmap.createBitmap(10, 10, Config.ARGB_8888); cacheCanvas = new Canvas(cachebBitmap); cacheCanvas.drawColor(Color.WHITE); } public void clear() { if (cacheCanvas != null) { paint.setColor(Color.WHITE); cacheCanvas.drawPaint(paint); paint.setColor(Color.BLACK); cacheCanvas.drawColor(Color.WHITE); invalidate(); } } @Override protected void onDraw(Canvas canvas) { // canvas.drawColor(BRUSH_COLOR); canvas.drawBitmap(cachebBitmap, 0, 0, null); canvas.drawPath(path, paint); } @Override protected void onSizeChanged(int w, int h, int oldw, int oldh) { int curW = cachebBitmap != null ? cachebBitmap.getWidth() : 0; int curH = cachebBitmap != null ? cachebBitmap.getHeight() : 0; if (curW >= w && curH >= h) { return; } if (curW < w) curW = w; if (curH < h) curH = h; Bitmap newBitmap = Bitmap.createBitmap(curW, curH, Bitmap.Config.ARGB_8888); Canvas newCanvas = new Canvas(); newCanvas.setBitmap(newBitmap); if (cachebBitmap != null) { newCanvas.drawBitmap(cachebBitmap, 0, 0, null); } cachebBitmap = newBitmap; cacheCanvas = newCanvas; } private float cur_x, cur_y; @Override public boolean onTouchEvent(MotionEvent event) { float x = event.getX(); float y = event.getY(); switch (event.getAction()) { case MotionEvent.ACTION_DOWN: { cur_x = x; cur_y = y; path.moveTo(cur_x, cur_y); break; } case MotionEvent.ACTION_MOVE: { path.quadTo(cur_x, cur_y, x, y); cur_x = x; cur_y = y; break; } case MotionEvent.ACTION_UP: { cacheCanvas.drawPath(path, paint); path.reset(); break; } } invalidate(); return true; } } }