開發中經常需要請求網絡獲取數據，我們在請求網絡到得到數據時當中需要等待一些時間，為了增加用戶體驗，我們一般會用一個Dialog來提示用戶我們在加載網絡數據。
今天我們來實現如下效果的加載中Dialog。
從圖中我們可以看到要這個Dialog是圖片還有文字組成的，(不過我這里使用代碼實現的，沒有用圖片)，以下是這個加載圖形的代碼：
public class LVCircularRing extends View {private float mWidth = 0f;private float mPadding = 0f;private float startAngle = 0f;private Paint mPaint;public LVCircularRing(Context context) { this(context, null);}public LVCircularRing(Context context, AttributeSet attrs) { this(context, attrs, 0);}public LVCircularRing(Context context, AttributeSet attrs, int defStyleAttr) { super(context, attrs, defStyleAttr); initPaint();}@Overrideprotected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { super.onMeasure(widthMeasureSpec, heightMeasureSpec); if (getMeasuredWidth() > getHeight()) mWidth = getMeasuredHeight(); else mWidth = getMeasuredWidth(); mPadding = 5;}@Overrideprotected void onDraw(Canvas canvas) { super.onDraw(canvas); mPaint.setColor(Color.argb(100, 255, 255, 255)); canvas.drawCircle(mWidth / 2, mWidth / 2, mWidth / 2 - mPadding, mPaint); mPaint.setColor(Color.WHITE); RectF rectF = new RectF(mPadding, mPadding, mWidth - mPadding, mWidth - mPadding); canvas.drawArc(rectF, startAngle, 100 , false, mPaint);//第四個參數是否顯示半徑}private void initPaint() { mPaint = new Paint(); mPaint.setAntiAlias(true); mPaint.setStyle(Paint.Style.STROKE); mPaint.setColor(Color.WHITE); mPaint.setStrokeWidth(8);}public void startAnim() { stopAnim(); startViewAnim(0f, 1f, 1000);}public void stopAnim() { if (valueAnimator != null) { clearAnimation(); valueAnimator.setRepeatCount(1); valueAnimator.cancel(); valueAnimator.end(); }}ValueAnimator valueAnimator;private ValueAnimator startViewAnim(float startF, final float endF, long time) { valueAnimator = ValueAnimator.ofFloat(startF, endF); valueAnimator.setDuration(time); valueAnimator.setInterpolator(new LinearInterpolator()); valueAnimator.setRepeatCount(ValueAnimator.INFINITE);//無限循環 valueAnimator.setRepeatMode(ValueAnimator.RESTART);// valueAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() { @Override public void onAnimationUpdate(ValueAnimator valueAnimator) { float value = (float) valueAnimator.getAnimatedValue(); startAngle = 360 * value; invalidate(); } }); valueAnimator.addListener(new AnimatorListenerAdapter() { @Override public void onAnimationEnd(Animator animation) { super.onAnimationEnd(animation); } }); if (!valueAnimator.isRunning()) { valueAnimator.start(); } return valueAnimator;}}Dialog 代碼：
public class LoadingDialog {LVCircularRing mLoadingView;Dialog mLoadingDialog;public LoadingDialog(Context context,String msg) { // 首先得到整個View View view = LayoutInflater.from(context).inflate( R.layout.loading_dialog_view, null); // 獲取整個布局 LinearLayout layout = (LinearLayout) view.findViewById(R.id.dialog_view); // 頁面中的LoadingView mLoadingView = (LVCircularRing) view.findViewById(R.id.lv_circularring); // 頁面中顯示文本 TextView loadingText = (TextView) view.findViewById(R.id.loading_text); // 顯示文本 loadingText.setText(msg); // 創建自定義樣式的Dialog mLoadingDialog = new Dialog(context, R.style.loading_dialog); // 設置返回鍵無效 mLoadingDialog.setCancelable(false); mLoadingDialog.setContentView(layout, new LinearLayout.LayoutParams( LinearLayout.LayoutParams.MATCH_PARENT, LinearLayout.LayoutParams.MATCH_PARENT));}public void show(){ mLoadingDialog.show(); mLoadingView.startAnim();}public void close(){ if (mLoadingDialog!=null) { mLoadingView.stopAnim(); mLoadingDialog.dismiss(); mLoadingDialog=null; }}}布局文件loading_dialog_view 代碼：
<?xml version="1.0" encoding="utf-8"?><LinearLayoutxmlns:android="http://schemas.android.com/apk/res/android"android:id="@+id/dialog_view"android:layout_width="match_parent"android:layout_height="match_parent"android:gravity="center"android:background="@drawable/dialog_bg"android:padding="20dp"android:orientation="vertical"><com.ye.daqiapp.ui.widget.loading.LVCircularRing android:id="@+id/lv_circularring" android:layout_width="50dp" android:layout_height="50dp"/><TextView android:id="@+id/loading_text" android:layout_width="wrap_content" android:layout_height="wrap_content" android:textColor="#ffffff" android:layout_marginTop="5dp" android:textSize="15sp"/></LinearLayout>
Dialog中Style代碼：
<style name="loading_dialog" parent="android:style/Theme.Dialog"> <item name="android:windowFrame">@null</item> <item name="android:windowNoTitle">true</item> <item name="android:windowBackground">@android:color/transparent</item> <item name="android:windowIsFloating">true</item> <item name="android:backgroundDimEnabled">false</item> <item name="android:windowContentOverlay">@null</item></style>
背景dialog_bg 代碼：
<?xml version="1.0" encoding="utf-8"?><shape xmlns:android="http://schemas.android.com/apk/res/android"><!-- 內部顏色 --><solid android:color="#444444" /><!-- 圓角的幅度 --><corners android:bottomLeftRadius="3dp" android:bottomRightRadius="3dp" android:topLeftRadius="3dp" android:topRightRadius="3dp" /></shape>
如何使用：在需要使用的地方初始化Dialog:
LoadingDialog dialog=new LoadingDialog(context,"玩命加載中...");//顯示Dialogdialog.show();//關閉Dialogdialog.close();
以上是對Android Dialog 重寫的小示例，有需要的朋友可以參考下。
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