android toast 未显示（尽管另一个显示）

Question

我遇到了一个问题，就是没有显示吐司。但是显示了第一个和第三个祝酒词，而第二个祝酒词使用完全相同的语法。上下文每次都应该相同。

我的应用程序没有崩溃，我已经尝试 runOnUiThread() 无济于事。

我一直在寻找答案已经有一段时间了，但似乎找不到问题背后的原因。

在此先感谢您的帮助

这不是全部class，但这就是它发生的地方

public class SendActivity extends AppCompatActivity {
    private static final int PICK_FILE = 0;
    private static final int REQUEST_PERMISSION_SMS_SEND = 1;
    private static final int REQUEST_PERMISSION_SMS_READ = 2;
    public static final int MESSAGE_CAPACITY = 114; //amount of bytes that can be transmitted per message //TODO check value
    public static final long MAX_FILE_SIZE = 400_000; //TODO replace with exact value (bytes)

    private Long fileSize;
    private String fileName;
    private android.net.Uri uri;
    private boolean inputOK;
    private boolean receivedAuthorization;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_send);
    }

    /**
     * Method called when the confirmation button is pressed. It will go to the transmitActivity
     * if it passes the verification
     *
     * @param view the view that called the method
     */
    public void transmitActivity(View view) {
        TextView tv = findViewById(R.id.numberInputInner);
        String number = tv.getText().toString();
        if (!inputOK || number.isEmpty() || !PhoneNumberUtils.isWellFormedSmsAddress(number)) { //only check if number is present and numerical
            // 1 SHOWN
            Toast.makeText(this, "Please enter a phone number and choose a correct file", Toast.LENGTH_LONG).show();
            return;
        }

        //check if allowed to send sms, else request
        if (ActivityCompat.checkSelfPermission(this, Manifest.permission.SEND_SMS) != PackageManager.PERMISSION_GRANTED) {
            ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.SEND_SMS}, REQUEST_PERMISSION_SMS_SEND);
            return;
        }

        //check if allowed to read sms, else request
        if (ActivityCompat.checkSelfPermission(this, Manifest.permission.READ_SMS) != PackageManager.PERMISSION_GRANTED) {
            ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.READ_SMS}, REQUEST_PERMISSION_SMS_READ);
            return;
        }

        try {
            receivedConfirmation = false;
            sendRequestMessage(); //sends an sms
            listenForResponse(); //creates a thread listening for response
            // 2 NOT SHOWN
            Toast.makeText(getApplicationContext(), "Waiting 15 sec for authorization from other party", Toast.LENGTH_LONG).show();
            Thread.sleep(15_000);
        } catch (InterruptedException e) {
            //TODO
        }

        if (!receivedConfirmation) {
            // 3 SHOWN
            Toast.makeText(this, "Didn't receive authorization to transfer the file. Try again", Toast.LENGTH_LONG).show();
            return;
        } else {
            Intent transmitActivity = new Intent(this, TransmitActivity.class);
            transmitActivity.putExtra("fileName", this.fileName);
            transmitActivity.putExtra("fileSize", this.fileSize);
            transmitActivity.putExtra("uri", this.uri);
            transmitActivity.putExtra("phoneNumber", tv.getText().toString());
            startActivity(transmitActivity);
        }
    }
}

Answer 1

您的代码在 UI 线程上运行并且 Thread.sleep() 阻止了它。 UI 线程不会处理其他任何事情，例如在屏幕上显示祝酒词。

切勿在 UI 线程上使用 Thread.sleep()。

您需要一些其他机制来处理异步操作，例如等待某事完成。回调方法是一种常用的方法。

Answer 2

请使用 activity 上下文“this”而不是 getApplicationContext()。应该可以。

注意：理想情况下，根据文档，它应该与 activity 或应用程序上下文一起使用。但根据我的经验，应用程序上下文并不是一直有效。

也不要在activity中使用Thread.sleep()方法。如果您正在寻找等待功能，请使用 postDelayed 方法和 Handler 例如：

final Handler handler = new Handler();
handler.postDelayed (() -> {
    //your code here
}, TIME_DELAY);

android toast 未显示（尽管另一个显示）

android toast not showing (though another does)

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