Android 以编程方式停止 toast 通知？

有没有办法以编程方式停止 Toast 消息？

假设我有一个按钮，单击它可以滚动 toast 消息，并且在 onclick 事件中我想停止队列中的所有消息并只显示新消息，我该怎么做？

我的代码的简化版本如下 - 代码：

public class Help extends Activity{

LinearLayout background;
int screenNo = 1;
Toast toast;

 /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.help);

       background = (LinearLayout) findViewById(R.id.helpLayout);

        ImageButton next = (ImageButton) findViewById(R.id.imageButtonNext);
        next.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View arg0) {
                toast.cancel();
                showNextScreen();
            }});        
 }

private void showMessageBox(String title, String msg) {
    AlertDialog.Builder b = new AlertDialog.Builder(this);
     b.setTitle(title);
     b.setMessage(msg);
     b.setPositiveButton("Next", new DialogInterface.OnClickListener() {
         public void onClick(DialogInterface arg0, int arg1) {
             showNextScreen();
        }});
     b.setNegativeButton("Quit Help", new DialogInterface.OnClickListener() {
         public void onClick(DialogInterface arg0, int arg1) {
                 returnHome();
        }});
     b.show();
 }

private void showNextScreen() {
    int time = 7000;
    String tstMsg = "error";    

    switch (screenNo) {
    case 1:
        break;          
    case 2:
        break;          
    case 3:
        break;          
    case 4:
        break;
    case 5:
        toast.cancel();
        returnHome();
        break;

    default:
        break;
    }

    if(screenNo < 5)
    {
    toast=Toast.makeText(this, tstMsg, time);   
    toast.setGravity(Gravity.BOTTOM, 0, 0);
    toast.show();
    screenNo++;
    }
}
}

这就是我实现这一目标的方法。

public static Toast toastShow;

public void showToast(Activity actRef, String message) {

    if (toastShow == null
            || toastShow.getView().getWindowVisibility() != View.VISIBLE) {
        toastShow = Toast.makeText(actRef, message, Toast.LENGTH_SHORT);
        toastShow.setGravity(Gravity.CENTER, 0, 0);
        toastShow.show();
    }
}

在单独的类中定义上面的代码并在您想要显示消息的地方实例化该类，您就完成了。