Android编程实现Toast只显示最后一条的方法

import android.content.Context;import android.graphics.PixelFormat;import android.os.Handler;import android.os.Looper;import android.os.Message;import android.view.Gravity;import android.view.WindowManager;import android.widget.TextView;import android.widget.Toast;public class ToastUtil {  //方法一  private static Handler mHandler = new Handler(Looper.getMainLooper());  private static Toast mToast = null;  private static Object synObject = new Object();  public static void showToastByThread(Context context, String msg){    showToastByThread(context, msg, Toast.LENGTH_SHORT);  }  public static void showToastByThread(Context context, int msg){    showToastByThread(context, context.getText(msg), Toast.LENGTH_SHORT);  }  public static void showToastByThread(final Context context, final CharSequence msg, final int length){    new Thread(new Runnable() {      @Override      public void run() {        mHandler.post(new Runnable() {          @Override          public void run() {            synchronized (synObject) {              if (mToast != null){                mToast.setText(msg);                mToast.setDuration(length);              }else{                mToast = Toast.makeText(context, msg, length);              }              mToast.show();            }          }        });      }    }).start();  }  //方法二:注意此方法不能再子线程中使用  private static long oneTime;  private static long twoTime;  private static String oldMsg;  public static void showToastByTime(Context context, String msg){    if (mToast == null) {      mToast = Toast.makeText(context, msg, Toast.LENGTH_SHORT);      mToast.show();      oneTime = System.currentTimeMillis();    } else {      twoTime = System.currentTimeMillis();      if (msg.equals(oldMsg)){        if (twoTime-oneTime > Toast.LENGTH_SHORT){          mToast.show();        }      } else {        oldMsg = msg;        mToast.setText(msg);        mToast.show();      }    }    oneTime = twoTime;  }  public static void showToastByTime(Context context, int msg){    showToastByTime(context, context.getString(msg));  }  //方法三  public static TextView mTextView;  public static WindowManager mWindowManager = null;  private static Handler mPriHandler = new Handler(){    @Override    public void handleMessage(Message msg) {      cancelToast();    }  };  public static void showToastByWindow(Context context, String msg){    mWindowManager = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);    if (mTextView == null){      mTextView = new TextView(context);    }    mTextView.setText(msg);    mTextView.setTextSize(20);    mTextView.setPadding(0, 0, 0, 30);    if (mTextView.getParent() == null){      WindowManager.LayoutParams params = new WindowManager.LayoutParams();      params.gravity= Gravity.BOTTOM;      params.alpha = 0.65f;      params.x = 0;      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 |          WindowManager.LayoutParams.FLAG_LAYOUT_IN_SCREEN;      params.format = PixelFormat.TRANSLUCENT;      params.windowAnimations = 0;      mWindowManager.addView(mTextView, params);      mPriHandler.sendEmptyMessageDelayed(101, 1000);    } else {      mTextView.setText(msg);      mPriHandler.removeMessages(101);      mPriHandler.sendEmptyMessageDelayed(101, 1000);    }  }  public static void cancelToast(){    if (mTextView != null && mTextView.getParent() != null){      mWindowManager.removeView(mTextView);    }  }}