[Android开发]Android 自定义Toast

系统Toast提示时不能够进行取消，如果有多个Toast时会很长时间才消失。自定义Toast通过WindowManager来进行手动的控制Toast的显示与隐藏。能有效的解决该问题。

Toast提示的布局

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="@android:drawable/toast_frame "
android:gravity="center"
android:orientation="horizontal" >
<ImageView
android:id="@+id/toast_img"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:visibility="gone" />
<TextView
android:id="@+id/toast_text"
android:layout_width="0dip"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:layout_weight="1"
android:textAppearance="@android:style/TextAppearance.Small"
android:textColor="#ffffffff" />
</LinearLayout>

/**
* 吐司提示的工具类，能够控制吐司的显示和隐藏
*/
public class ToastUtil {
public static final int LENGTH_SHORT = 0;
public static final int LENGTH_LONG = 1;
private static View toastView;
private WindowManager mWindowManager;
private static int mDuration;
private final int WHAT = 100;
private static View oldView;
private static Toast toast;
private static CharSequence oldText;
private static CharSequence currentText;
private static ToastUtil instance = null;
private static TextView textView;
private ToastUtil(Context context) {
mWindowManager = (WindowManager) context.getApplicationContext()
.getSystemService(Context.WINDOW_SERVICE);
toastView = LayoutInflater.from(context).inflate(R.layout.toast_view,
null);
textView = (TextView) toastView.findViewById(R.id.toast_text);
toast = Toast.makeText(context, "", Toast.LENGTH_SHORT);
}
private static ToastUtil getInstance(Context context) {
if (instance == null) {
synchronized (ToastUtil.class) {
if (instance == null)
instance = new ToastUtil(context);
}
}
return instance;
}
public static ToastUtil makeText(Context context, CharSequence text,
int duration) {
ToastUtil util = getInstance(context);
mDuration = duration;
toast.setText(text);
currentText = text;
textView.setText(text);
return util;
}
public static ToastUtil makeText(Context context, int resId, int duration{
ToastUtil util = getInstance(context);
mDuration = duration;
toast.setText(resId);
currentText = context.getResources().getString(resId);
textView.setText(context.getResources().getString(resId));
return util;
}
/**
* 进行Toast显示，在显示之前会取消当前已经存在的Toast
*/
public void show() {
long time = 0;
switch (mDuration) {
case LENGTH_SHORT:
time = 2000;
break;
case LENGTH_LONG:
time = 3500;
break;
default:
time = 2000;
break;
}
if (currentText.equals(oldText) && oldView.getParent() != null) {
toastHandler.removeMessages(WHAT);
toastView = oldView;
oldText = currentText;
toastHandler.sendEmptyMessageDelayed(WHAT, time);
return;
}
cancelOldAlert();
toastHandler.removeMessages(WHAT);
WindowManager.LayoutParams params = new WindowManager.LayoutParams();
params.height = WindowManager.LayoutParams.WRAP_CONTENT;
params.width = WindowManager.LayoutParams.WRAP_CONTENT;
params.flags = WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE
| WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE
| WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON;
params.format = PixelFormat.TRANSLUCENT;
params.windowAnimations = android.R.style.Animation_Toast;
params.type = WindowManager.LayoutParams.TYPE_TOAST;
params.setTitle("Toast");
params.gravity = toast.getGravity();
params.y = toast.getYOffset();
if (toastView.getParent() == null) {
mWindowManager.addView(toastView, params);
}
oldView = toastView;
oldText = currentText;
toastHandler.sendEmptyMessageDelayed(WHAT, time);
}
private Handler toastHandler = new Handler() {
@Override
public void handleMessage(Message msg) {
super.handleMessage(msg);
cancelOldAlert();
int id = msg.what;
if (WHAT == id) {
cancelCurrentAlert();
}
}
};
private void cancelOldAlert() {
if (oldView != null && oldView.getParent() != null) {
mWindowManager.removeView(oldView);
}
}
public void cancelCurrentAlert() {
if (toastView != null && toastView.getParent() != null) {
mWindowManager.removeView(toastView);
}
}
}

在某些Pad上面Toast显示出来后就不会自动消失，在这些Pad上toastView.getParent()会为nul这样就导致无法移除。可以将cancelOldAlert()以及
cancelCurrentAlert()进行如下修改。

private void cancelOldAlert() {
if (oldView != null) { // 去掉 oldView.getParent() != null 这个参数，然后加上try catch代码块，解决在部分Pad上oldView.getParent()不准确的问题
try {
mWindowManager.removeView(oldView);
} catch (Exception e) {
e.printStackTrace();
}
}
}
public void cancelCurrentAlert() {
if (toastView != null) {
try {
// 去掉 oldView.getParent() != null 这个参数，然后加上try catch代码块，解决在部分Pad上oldView.getParent()不准确的问题
mWindowManager.removeView(toastView);
} catch (Exception e) {
e.printStackTrace();
}
} else if (oldView != null) {
try {
mWindowManager.removeView(oldView);
} catch (Exception e) {
e.printStackTrace();
}
}
}