android 加载图片并在上面画图

发布时间:2016-12-9 0:17:06 编辑:www.fx114.net 分享查询网我要评论
本篇文章主要介绍了"android 加载图片并在上面画图",主要涉及到android 加载图片并在上面画图方面的内容,对于android 加载图片并在上面画图感兴趣的同学可以参考一下。

像Ps上的应用一样,我们加载一个图片然后在上面增加各种我们需要的挂件,文字效果等。我们今天完成一个简单的Demo package com.example.fingerdraw; import java.io.FileNotFoundException; import java.io.OutputStream; import android.app.Activity; import android.content.ContentValues; import android.content.Intent; import android.graphics.Bitmap; import android.graphics.Bitmap.CompressFormat; import android.graphics.BitmapFactory; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.Matrix; import android.graphics.Paint; import android.net.Uri; import android.os.Bundle; import android.provider.MediaStore.Images.Media; import android.view.Display; import android.view.MotionEvent; import android.view.View; import android.view.View.OnClickListener; import android.view.View.OnTouchListener; import android.widget.Button; import android.widget.ImageView; import android.widget.Toast; public class MainActivity extends Activity implements OnTouchListener, OnClickListener { private ImageView image; private Paint paint; private Canvas canvas; private Bitmap bitmap; private Bitmap alterBitmap; private Button choose; private Button save; private final static int RESULT = 0; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); image = (ImageView) findViewById(R.id.image); choose = (Button) findViewById(R.id.chooseButton); save=(Button)findViewById(R.id.saveButton); /* * bitmap = Bitmap.createBitmap(getWindowManager().getDefaultDisplay() * .getWidth(), getWindowManager().getDefaultDisplay().getHeight(), * Bitmap.Config.ARGB_8888); canvas = new Canvas(bitmap);// 画板 paint = * new Paint();// 画刷 paint.setColor(Color.BLUE); * image.setImageBitmap(bitmap); */ image.setOnTouchListener(this); choose.setOnClickListener(this); save.setOnClickListener(this); } private float downx = 0; private float downy = 0; private float upx = 0; private float upy = 0; public boolean onTouch(View v, MotionEvent event) { int action = event.getAction(); switch (action) { case MotionEvent.ACTION_DOWN: downx = event.getX(); downy = event.getY(); break; case MotionEvent.ACTION_MOVE: // 路径画板 upx = event.getX(); upy = event.getY(); canvas.drawLine(downx, downy, upx, upy, paint); image.invalidate(); downx = upx; downy = upy; break; case MotionEvent.ACTION_UP: // 直线画板 upx = event.getX(); upy = event.getY(); canvas.drawLine(downx, downy, upx, upy, paint); image.invalidate();// 刷新 break; default: break; } return true; } public void onClick(View arg0) { if(arg0==choose){ Intent intent = new Intent(Intent.ACTION_PICK, android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI); startActivityForResult(intent, RESULT); }else if(arg0==save){ //保存画好的图片 if(alterBitmap!=null){ try { Uri imageUri=getContentResolver().insert(Media.EXTERNAL_CONTENT_URI, new ContentValues()); OutputStream outputStream=getContentResolver().openOutputStream(imageUri); alterBitmap.compress(CompressFormat.PNG, 90, outputStream); Toast.makeText(getApplicationContext(), "save!", Toast.LENGTH_SHORT).show(); } catch (FileNotFoundException e) { e.printStackTrace(); } } } } @Override protected void onActivityResult(int requestCode, int resultCode, Intent data) { // TODO Auto-generated method stub super.onActivityResult(requestCode, resultCode, data); if (resultCode == RESULT_OK) { Uri imageFileUri = data.getData(); Display display = getWindowManager().getDefaultDisplay(); float dw = display.getWidth(); float dh = display.getHeight(); try { BitmapFactory.Options options = new BitmapFactory.Options(); options.inJustDecodeBounds = true; bitmap = BitmapFactory.decodeStream(getContentResolver() .openInputStream(imageFileUri), null, options); int heightRatio = (int) Math.ceil(options.outHeight / dh); int widthRatio = (int) Math.ceil(options.outWidth / dw); if (heightRatio > 1 && widthRatio > 1) { if (heightRatio > widthRatio) { options.inSampleSize = heightRatio; } else { options.inSampleSize = widthRatio; } } options.inJustDecodeBounds = false; bitmap = BitmapFactory.decodeStream(getContentResolver() .openInputStream(imageFileUri), null, options); alterBitmap = Bitmap.createBitmap(bitmap.getWidth(), bitmap.getHeight(), bitmap.getConfig()); canvas = new Canvas(alterBitmap); paint = new Paint(); paint.setColor(Color.GREEN); paint.setStrokeWidth(10); Matrix matrix = new Matrix(); canvas.drawBitmap(bitmap, matrix, paint); image.setImageBitmap(alterBitmap); image.setOnTouchListener(this); } catch (FileNotFoundException e) { e.printStackTrace(); } } } }   效果:

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