小编Soh*_*ail的帖子

我正在尝试创建一个AlertDialog但按钮没有显示.仅在Android 7.0中看到此问题:

final AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setTitle("This app needs location access");
builder.setMessage("Please grant location access so this app can detect beacons.");
builder.setPositiveButton(android.R.string.ok, null);
builder.setOnDismissListener(new DialogInterface.OnDismissListener() {
    @Override
    @TargetApi(Build.VERSION_CODES.M)
    public void onDismiss(final DialogInterface dialog) {
        requestPermissions(new String[]{Manifest.permission.ACCESS_COARSE_LOCATION}, PERMISSION_REQUEST_COARSE_LOCATION);
    }
});
builder.show();

我有一个7GB的csv文件,我想分成更小的块,所以它在笔记本上用Python进行分析是可读的和更快的.我想从中拿一小套,也许是250MB,所以我该怎么做呢？