Android开发小技巧总结
jopen
12年前
总结下一些相关技巧。 <p><b>1 </b><b>全屏</b></p> <p align="left"></p> <pre class="brush:java; toolbar: true; auto-links: false;">super.onCreate(savedInstanceState); getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN); requestWindowFeature(Window.FEATURE_NO_TITLE); setContentView(R.layout.main);</pre> <p></p> <p><b>2 </b><b>取得屏幕像素</b></p> <p align="left"></p> <pre class="brush:java; toolbar: true; auto-links: false;">DisplayMetrics dm=new DisplayMetrics(); getWindowManager().getDefaultDisplay().getMetrics(dm);</pre> <p></p> <p><b>3 </b><b>简单拍照</b></p> <p align="left"></p> <pre class="brush:java; toolbar: true; auto-links: false;">button.setOnClickListener(new OnClickListener(){ @Override public void onClick(View arg0) { Intent intent = new Intent("android.media.action.IMAGE_CAPTURE"); startActivityForResult(intent,SELECT_PICTURE_FROM_CAMERA); } }); //然后重载startActivityForResult添加自己的实现 @Override protected void onActivityResult(int requestCode, int resultCode, Intent data) { if( resultCode==RESULT_OK) { if(requestCode==SELECT_PICTURE_FROM_CAMERA) { File image=new File(Environment.getExternalStorageDirectory(), "camera.jpg"); selectedImagePath=image.getAbsolutePath(); Drawable d=Drawable.createFromPath(selectedImagePath); ImageView.setImageDrawable(d); } } } </pre> <p></p> <p><b>4 </b><b>从</b><b>android</b><b>本地多媒体图片文件夹中选择图片</b></p> <p align="left"></p> <pre class="brush:java; toolbar: true; auto-links: false;">Intent i=new Intent(Intent.ACTION_GET_CONTENT); i.setType("image/*"); Intent wrapi=Intent.createChooser(i, "choose"); startActivityForResult(wrapi, SELECT_PICTURE_FROM_FILE); //然后重载startActivityForResult添加自己的实现 @Override protected void onActivityResult(int requestCode, int resultCode, Intent data) { if( resultCode==RESULT_OK) { if(requestCode==SELECT_PICTURE_FROM_FILE ) { Uri selectedImageUri = data.getData(); selectedImagePath=getPath(selectedImageUri); imageView.setImageURI(selectedImageUri); } } } //获取当前选择的图片，并显示在imageView上 private String getPath(Uri uri) { String[] projection={MediaStore.Images.Media.DATA}; Cursor cursor=managedQuery(uri,projection,null,null,null); int column_index=cursor.getColumnIndexOrThrow(MediaStore.Images.Media.DATA); cursor.moveToFirst(); return cursor.getString(column_index); } //Query实现从图片数据库中查询到所要记录</pre> <p></p> <p><b>5 Activity</b><b>之间带内容的跳转</b></p> <p align="left"></p> <pre class="brush:java; toolbar: true; auto-links: false;">Intent intent = new Intent(); Bundle imageMsg = new Bundle(); imageMsg.putString("filePath", selectedImagePath); / intent.putExtras(imageMsg); intent.setClass(ActivityA.this,ActivityB.class); startActivity(intent); ActivityA.this.finish();</pre> <p></p> <p><b>6 </b><b>位图缩放</b></p> <p align="left"><b>public</b> Bitmap zoomImage(Bitmap bgimage, <b>int</b> newWidth, <b>int</b> newHeight) { </p> <p align="left"> <b>int</b> width = bgimage.getWidth();</p> <p align="left"> <b>int</b> height = bgimage.getHeight();</p> <p align="left"> </p> <p align="left"> Matrix matrix = <b>new</b> Matrix();</p> <p align="left"> </p> <p align="left"> <b>float</b> scaleWidth = ((<b>float</b>) newWidth) / width;</p> <p align="left"> <b>float</b> scaleHeight = ((<b>float</b>) newHeight) / height;</p> <p align="left"> </p> <p align="left"> matrix.postScale(scaleWidth, scaleHeight);</p> <p align="left"> Bitmap bitmap = Bitmap.<i>createBitmap</i>(bgimage, 0, 0, width, height,</p> <p align="left"> matrix, <b>true</b>);</p> <p align="left"> <b>return</b> bitmap;</p> <p align="left"> </p> <p> }</p> <p><b>7 Gallery</b><b>的使用</b></p> <p>Gallery gallery=(Gallery)findViewById(R.id.<i>gallery</i>);</p> <p align="left"> myImageAdapter imageadapter=<b>new</b> myImageAdapter(<b>this</b>); //传入context</p> <p align="left"> gallery.setAdapter(imageadapter);</p> <p align="left"> gallery.setOnItemClickListener(<b>new</b> Gallery.OnItemClickListener(){</p> <p align="left"> @Override</p> <p align="left"> <b>public</b> <b>void</b> onItemClick(AdapterView<?> arg0, View arg1, <b>int</b> arg2,<b>long</b> arg3) {</p> <p align="left"> Bitmap selectedBitmap=BitmapFactory.<i>decodeResource</i>(getResources(),imageadapter.myImageIds[arg2]);</p> <p align="left"> }</p> <p align="left"> });</p> <p> gallery.setSelection(1);</p> <p>//adapter的类定义</p> <p align="left"><b>public</b> <b>class</b> myImageAdapter <b>extends</b> BaseAdapter{</p> <p align="left"> </p> <p align="left"> <b>int</b> mGalleryItemBackground;</p> <p align="left"> <b>private</b> Context context;</p> <p align="left"> <b>public</b> Integer[] myImageIds={</p> <p align="left"> //图片的资源id号</p> <p align="left"> };</p> <p align="left"> <b>public</b> myImageAdapter(Context context)</p> <p align="left"> {</p> <p align="left"> <b>this</b>.context=context;</p> <p align="left"> TypedArray typed_array=context.obtainStyledAttributes(R.styleable.<i>Gallery</i>);</p> <p align="left"> </p> <p align="left"> mGalleryItemBackground=typed_array.getResourceId(R.styleable.<i>Gallery_android_galleryItemBackground</i> , 0);</p> <p align="left"> //mGalleryItemBackground++;</p> <p align="left"> typed_array.recycle();</p> <p align="left"> }</p> <p align="left"> @Override</p> <p align="left"> <b>public</b> <b>int</b> getCount() {</p> <p align="left"> // <b>TODO</b> Auto-generated method stub</p> <p align="left"> <b>return</b> myImageIds.length;</p> <p align="left"> }</p> <p align="left"> </p> <p align="left"> @Override</p> <p align="left"> <b>public</b> Object getItem(<b>int</b> arg0) {</p> <p align="left"> // <b>TODO</b> Auto-generated method stub</p> <p align="left"> <b>return</b> arg0;</p> <p align="left"> }</p> <p align="left"> </p> <p align="left"> @Override</p> <p align="left"> <b>public</b> <b>long</b> getItemId(<b>int</b> arg0) {</p> <p align="left"> // <b>TODO</b> Auto-generated method stub</p> <p align="left"> <b>return</b> arg0;</p> <p align="left"> }</p> <p align="left"> </p> <p align="left"> @Override</p> <p align="left"> <b>public</b> View getView(<b>int</b> arg0, View arg1, ViewGroup arg2) {</p> <p align="left"> // <b>TODO</b> Auto-generated method stub</p> <p align="left"> ImageView imageView=<b>new</b> ImageView(context);</p> <p align="left"> imageView.setImageResource(myImageIds[arg0]);</p> <p align="left"> </p> <p align="left"> imageView.setScaleType(ImageView.ScaleType.<i>FIT_XY</i>);</p> <p align="left"> imageView.setLayoutParams(<b>new</b> Gallery.LayoutParams(128,128));</p> <p align="left"> imageView.setBackgroundResource(mGalleryItemBackground);</p> <p align="left"> <b>return</b> imageView;</p> <p align="left"> }</p> <p align="left"> </p> <p>}</p> <p><b>8 activity</b><b>中使用线程</b></p> <p>private Handler mHandler=new Handler();</p> <p align="left"><b>private</b> Runnable mRunnable=<b>new</b> Runnable()</p> <p align="left"> {</p> <p align="left"> @Override</p> <p align="left"> <b>public</b> <b>void</b> run() {</p> <p align="left"> // <b>TODO</b> Auto-generated method stub</p> <p align="left"> }</p> <p>};</p> <p>mHandler.post(mRunnable); //启动线程</p> <p><b>9 </b><b>保存到</b><b>android</b><b>多媒体图片文件夹</b></p> <p>android.provider.MediaStore.Images.Media.<i>insertImage</i>(getContentResolver(),resultBitmap, "picName", "descrition");</p> <p><b>10 </b><b>其他技巧摘录自网络，见链接</b></p> <p>1 <a href="/misc/goto?guid=4959517936175517299">android开发环境安装</a></p> <p>2 Android模拟器中使用sdcard</p> <p><a href="/misc/goto?guid=4959517936252758589">http://blog.csdn.net/unix_fans/archive/2009/08/20/4465038.aspx</a></p> <p><a href="/misc/goto?guid=4959517936329168599">http://blog.csdn.net/jinlking/archive/2009/03/03/3953319.aspx</a></p> <p>3 <b><a href="/misc/goto?guid=4959517936413501041">Android Intent 大全</a></b></p> <p>在Android中调用图片视频、音频、录音、拍照：</p> <p><a href="/misc/goto?guid=4959517936499357407">http://blog.csdn.net/bdwgbdwg/archive/2010/11/23/6029208.aspx</a></p> <p>4 <a href="/misc/goto?guid=4959517936575807252">Android.Content.Provider.rar</a></p> <p>5 <a href="/misc/goto?guid=4959517936662943951">Android中三种使用线程的方法.rar</a></p> <p><strong>11 Activity之间动态跳转(摘自网络)</strong></p> <p>//页面跳转<br /> int version = Integer.valueOf(android.os.Build.VERSION.SDK); <br /> if (version >= 5 ) { <br /> overridePendingTransition(R.anim.zoomin, R.anim.zoomout); //此为自定义的动画效果，下面两个为系统的动画效果 <br /> //overridePendingTransition(android.R.anim.fade_in,android.R.anim.fade_out); <br /> //overridePendingTransition(android.R.anim.slide_in_left,android.R.anim.slide_out_right); <br /> } <br /> //页面跳转</p> <p> //zoomin.xml</p> <p><?xml version="1.0" encoding="utf-8"?><br /> <set xmlns:android="<a href="/misc/goto?guid=4959517936744177530">http://schemas.android.com/apk/res/android</a>" <br /> android:interpolator="@android:anim/decelerate_interpolator" > <br /> <scale android:fromXScale="2.0" android:toXScale= "1.0" <br /> android:fromYScale="2.0" android:toYScale= "1.0" <br /> android:pivotX="50%p" android:pivotY= "50%p" <br /> android:duration="@android:integer/config_mediumAnimTime" /><br /> </set><br /> //zoomout.xml</p> <p><?xml version="1.0" encoding="utf-8"?><br /> <set xmlns:android="<a href="/misc/goto?guid=4959517936744177530">http://schemas.android.com/apk/res/android</a>" <br /> android:interpolator="@android:anim/decelerate_interpolator" <br /> android:zAdjustment="top" > <br /> <scale android:fromXScale="1.0" android:toXScale= ".5" <br /> android:fromYScale="1.0" android:toYScale= ".5" <br /> android:pivotX="50%p" android:pivotY= "50%p" <br /> android:duration="@android:integer/config_mediumAnimTime" /> <br /> <alpha android:fromAlpha="1.0" android:toAlpha= "0" <br /> android:duration="@android:integer/config_mediumAnimTime" /> <br /> </set></p> <p><strong>12 模拟按钮press和release的效果</strong></p> <p><a href="/misc/goto?guid=4959517936834912022">http://blog.csdn.net/sytzz/archive/2010/06/16/5673662.aspx</a></p> <p><strong>13 实现画出一个透明的点</strong></p> <p> Paint paint=new Paint();</p> <p> paint.setColor(Color.BLUE); <br /> paint.setAlpha(0); </p> <p> canvas.drawPoint(x, y, paint);</p> <p> 这样就好了吗？ no，你需要把你的canvas建立在一个允许透明的bitmap上，如下</p> <p> blankBitmap=Bitmap.createBitmap(picWidth, picHeight, Config.ARGB_8888);//不是Config.sRGB_565<br /> Canvas c = new Canvas(blankBitmap); </p> <br /> 作者： <a href="/misc/goto?guid=4959517936907596573" target="_blank">Aga.J</a> <br /> 出处： <a href="/misc/goto?guid=4959517935595607054" target="_blank">http://www.cnblogs.com/aga-j</a>