java - 在 fragment 开始之前显示 toast

Question

我是 Android 初学者，正在尝试编写一个简单的应用程序。当进入 fragment 时，单击按钮启动其他 fragment ，为此目的:

@Override
public void onClick(View v) {
    new Handler(Looper.getMainLooper()).post(new Runnable() {
        @Override
        public void run() {
            Toast.makeText(getActivity(), "Hello", Toast.LENGTH_SHORT).show();
            FragmentTransaction transaction = getActivity().getSupportFragmentManager().beginTransaction();
            secondFragment.removeAllViews();
            transaction.replace(R.id.secondFragment, new DashBoardFragment());
            transaction.commit();
        }
    });
}

但在其他 fragment 开始后显示 Hello Toast，但我想在 fragment 开始之前显示。

Answer 1

在 toast 之后在onClick中尝试这个:-

new Handler().postDelayed(new Runnable() {
    @Override
    public void run() {
        FragmentTransaction transaction = getActivity().getSupportFragmentManager().beginTransaction();
        secondFragment.removeAllViews();
        transaction.replace(R.id.secondFragment, new DashBoardFragment());
        transaction.commit();
    }
}, Toast.LENGTH_SHORT);

您的 fragment 交易将在 1500 毫秒后发生(因此您的 Toast 消息将在交易发生之前弹出)

您的完整点击方法...

@Override
public void onClick(View v) {
    Toast.makeText(getActivity(), "Hello", Toast.LENGTH_SHORT).show();
    new Handler().postDelayed(new Runnable() {
        @Override
        public void run() {
            FragmentTransaction transaction = getActivity().getSupportFragmentManager().beginTransaction();
            secondFragment.removeAllViews();
            transaction.replace(R.id.secondFragment, new DashBoardFragment());
            transaction.commit();    
        }  
    }, Toast.LENGTH_SHORT);              
}