java - onPreExecute方法没有被调用

Question

我正在尝试显示 Toast当我调用AsyncTask时与 new saveWithStickers(BaseActivity.this).execute(); 一起上课当我运行 onPreExecute() 下面的代码时，通知用户保存过程正在启动由于某种逻辑原因未调用方法，因此 Toast 也不会出现，是 runOnUiThread这种行为的原因是什么？

@SuppressLint("StaticFieldLeak")
public class saveWithStickers extends AsyncTask<Void, File, File> {
    File fileSaved;
    Context mContext;

    saveWithStickers(Context context) {
        mContext = context;
    }

    @Override
    protected File doInBackground(Void... voids) {
        fileSaved = FileUtil.getNewFile(BaseActivity.this, "VAPOGRAM");
        if (fileSaved != null)
            runOnUiThread(() -> {
                stickerView.save(fileSaved, true);
            });
        return fileSaved;
    }

    @SuppressLint("SetTextI18n")
    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        content.setVisibility(View.GONE);
        Toast.makeText(mContext, "saving ...", Toast.LENGTH_SHORT).show();
    }

    @Override
    protected void onPostExecute(File file) {
        super.onPostExecute(file);
}


saveButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                CheckPermissionUtil checkPermissionUtil = new CheckPermissionUtil(BaseActivity.this);
                if (Build.VERSION.SDK_INT >= 23) {
                    if (checkPermissionUtil.checkPermission(1812)) {
                        new saveWithStickers(BaseActivity.this).execute();
                    } else
                        checkPermissionUtil.requestPermission(1812);
                } else {
                    new saveWithStickers(BaseActivity.this).execute();
                }
            }
        });

Answer 1

用此替换您的代码

@SuppressLint("StaticFieldLeak")
        public class saveWithStickers extends AsyncTask<Void, File, File> {
            File fileSaved;
            Context mContext;

            saveWithStickers(Context context) {
                mContext = context;
            }

            @Override
            protected File doInBackground(Void... voids) {
                fileSaved = FileUtil.getNewFile(BaseActivity.this, "PHOTO EDITOR");
                if (fileSaved != null)
                    runOnUiThread(() -> stickerView.save(fileSaved, true));
                return fileSaved;
            }

            @SuppressLint("SetTextI18n")
            @Override
            protected void onPreExecute() {
                super.onPreExecute();
                Toast.makeText(mContext, "Saving ...", Toast.LENGTH_SHORT).show();
            }

            @Override
            protected void onPostExecute(File file) {
                super.onPostExecute(file);

        }
    }

要访问上下文，您需要传递它或使用 WeakRerefence到您的家长 Activity