Android Develop Tricks—1

Android Develop Tricks—1
Android Develop Tricks設定AlertDialog的大小：

AlertDialog dialog = builder.setTitle("訊息列表").setView(layout).create();dialog.show();//設定視窗的大小dialog.getWindow().setLayout(300, 200);

dialog.show();一定要放在dialog.getWindow().setLayout(300, 200);的前面，否則不起作用。

另一種實現：

WindowManager.LayoutParams params = dialog.getWindow().getAttributes();params.width = 300;params.height = 200;dialog.getWindow().setAttributes(params);

實際上setLayout就是對這個方法的封裝：

        final WindowManager.LayoutParams attrs = getAttributes();        attrs.width = width;        attrs.height = height;        if (mCallback != null) {            mCallback.onWindowAttributesChanged(attrs);        }

任意位置顯示View：

通過WindowManager來實現添加View：

mWindowManager = getWindowManager();          LayoutInflater inflater = (LayoutInflater) getSystemService(LAYOUT_INFLATER_SERVICE);          mDialogView = inflater.inflate(R.layout.dialogview, null);          WindowManager.LayoutParams params = new WindowManager.LayoutParams();          params.height = WindowManager.LayoutParams.WRAP_CONTENT;          params.width = WindowManager.LayoutParams.WRAP_CONTENT;          params.y += 100;          params.x += -30;          initDialogComponents(mDialogView);          //添加對話方塊          mWindowManager.addView(mDialogView, params);

任意View的觸摸移動通用方法：同樣是重寫onTouchEent

package ui;import android.content.Context;import android.util.AttributeSet;import android.util.DisplayMetrics;import android.util.Log;import android.view.MotionEvent;import android.view.WindowManager;import android.view.animation.AlphaAnimation;import android.view.animation.Animation;import android.view.animation.AnimationSet;import android.view.animation.ScaleAnimation;import android.widget.Button;/** *  * @author chenxiruanhai *  * */public class MenuButton extends Button {private Context mContext;private WindowManager mWm;int lastX;int lastY;int screenWidth;int screenHeight;public MenuButton(Context context, AttributeSet attrs) {super(context, attrs);this.mContext = context;mWm = (WindowManager) mContext.getSystemService(Context.WINDOW_SERVICE);DisplayMetrics dm = mContext.getResources().getDisplayMetrics();screenWidth = dm.widthPixels;screenHeight = dm.heightPixels;}@Overridepublic boolean onTouchEvent(MotionEvent event) {super.onTouchEvent(event);measure(0, 0);switch (event.getAction()) {case MotionEvent.ACTION_DOWN:lastX = (int) event.getRawX();lastY = (int) event.getRawY();break;case MotionEvent.ACTION_MOVE:int dx = (int) event.getRawX() - lastX;int dy = (int) event.getRawY() - lastY;int left = this.getLeft() + dx;int top = this.getTop() + dy;int right = this.getRight() + dx;int bottom = this.getBottom() + dy;if (left < 0) {left = 0;right = left + this.getWidth();}if (right > screenWidth) {right = screenWidth;left = right - this.getWidth();}if (top < 0) {top = 0;bottom = top + this.getHeight();}if (bottom > screenHeight) {bottom = screenHeight;top = bottom - this.getHeight();}this.layout(left, top, right, bottom);lastX = (int) event.getRawX();lastY = (int) event.getRawY();lastX = (int) event.getRawX();lastY = (int) event.getRawY();break;case MotionEvent.ACTION_UP:{Animation alphaAnimation = new AlphaAnimation( 0.5f,1f); alphaAnimation.setDuration(1000); Animation scaleAnimation2 = new ScaleAnimation(1.0f, .5f,1.0f,.5f); scaleAnimation2.setDuration(500); AnimationSet animationSet = new AnimationSet(true); animationSet.addAnimation(alphaAnimation); animationSet.addAnimation(scaleAnimation); animationSet.addAnimation(scaleAnimation2); animationSet.setFillAfter(true);Animation currentAnima = getAnimation();if(null!=currentAnima) {currentAnima.cancel();animationSet.reset();} startAnimation(animationSet);}break;}return true;}}

ImageView設定屬性scaleType為FIT_START後去掉多餘空白

imageView.setScaleType(ImageView.FIT_START);        imageView.setAdjustViewBounds(true);