Android:在一个单独的线程中输入对话框时Wait()主线程

Question

我正在Android中编写一个用户修改SQL数据库的活动.UI由用户输入名称的EditText和用户输入人物吸引力的Seekbar组成.下面有一堆按钮:添加,编辑,查看,删除.

当用户单击"编辑"按钮时,将显示一个输入对话框,要求用户输入记录编号.完成后,将加载该记录.

我遇到的问题是inputdialog会显示,而当用户输入记录no时,编辑方法的其余部分将继续进行,以便当用户输入输入时 - 没有任何事情发生,因为该功能已经已经完成.

为了解决这个问题,我决定使用多线程(我没有太多使用经验).当按下编辑按钮时,主UI线程被阻止(使用wait() - 这是因为我不希望UI在用户输入记录ID时处于活动状态.)并且输入对话框显示在单独的线程.

输入输入后,将通知线程并继续编辑功能的其余部分.(代码如下).

问题是,当我在UI线程上调用wait函数时,我收到一条错误,上面写着"对象在wait()之前没有被线程锁定".如何锁定UI线程？

我知道一般不应该阻止UI线程,但我认为在这种情况下它是可以的,因为我不希望它接受任何用户输入.

谢谢你的帮助.

public class Attractivometer extends Activity implements OnClickListener {

    private Button      buttonAddRecord,    buttonEditRecord,   buttonSaveChanges;
    private Button      buttonDeleteRecord, buttonViewRecord;
    private EditText    fieldName;
    private SeekBar     seekbarAttractiveness;
    private String      inputFromInputDialog=null;
    private Thread      inputThread;


    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.Attractivometer);

        buttonAddRecord         = (Button) findViewById(R.id.buttonAddRecord);
        buttonSaveChanges       = (Button) findViewById(R.id.buttonSaveChanges);
        buttonEditRecord        = (Button) findViewById(R.id.buttonEditRecord);
        buttonDeleteRecord      = (Button) findViewById(R.id.buttonDeleteRecord);
        buttonViewRecord        = (Button) findViewById(R.id.buttonViewRecord);

        fieldName               = (EditText) findViewById(R.id.fieldName);

        seekbarAttractiveness           = (SeekBar) findViewById(R.id.seekbarAttractiveness);

        buttonAddRecord.setOnClickListener(this);
        buttonSaveChanges.setOnClickListener(this);
        buttonEditRecord.setOnClickListener(this);
        buttonDeleteRecord.setOnClickListener(this);
        buttonViewRecord.setOnClickListener(this);
    }


    public void onClick(View clickedItem)
    {

        switch(clickedItem.getId())
        {
        case R.id.buttonAddRecord:
            //.....
            break;


        case R.id.buttonSaveChanges:
          //... 
            break;

        case R.id.buttonEditRecord:

            inputThread = new Thread(new Runnable(){

                public void run()
                {
                    showInputDialog("Enter Record ID", InputType.TYPE_CLASS_NUMBER);
                }

            });
            inputThread.start();


            try {
                Thread.currentThread().wait();
            } catch (InterruptedException e) {
                Log.e("Attractivometer","Main Thread interrupted while waiting");
                e.printStackTrace();
            }

            try {
                inputThread.join();
            } catch (InterruptedException e) {
                Log.e("Attractivometer","Input Thread interrupted while joining");
                e.printStackTrace();
            }

            int recordId = Integer.parseInt(inputFromInputDialog);
            if(recordId!=null)
            {
                AttractivometerSQLHandler AttractivometerDatabaseHandler = new AttractivometerSQLHandler(this);
                AttractivometerDatabaseHandler.openDatabase();
                String recordName = AttractivometerDatabaseHandler.getName(recordId);
                String recordAttractiveness = AttractivometerDatabaseHandler.getAttractiveness(recordId);

                if(recordName==null || recordAttractiveness==null )
                {
                    //no record found.
                    Toast.makeText(this, "No record with that ID found", Toast.LENGTH_SHORT).show();
                }else
                {
                    fieldName.setText(recordName);
                    seekbarAttractiveness.setProgress( Integer.parseInt(recordAttractiveness) );
                    recordIsOpen(true);
                }


                AttractivometerDatabaseHandler.closeDatabase();
            }else
                //No input.
            recordIsOpen(false);

            break;

        case R.id.buttonDeleteRecord:
            //...
            break;

        case R.id.buttonViewRecord:
            //....

        }
    }

    private void showInputDialog(String prompt, int inputType)
    {
        AlertDialog.Builder inputDialog = new AlertDialog.Builder(this);

        inputDialog.setTitle("Record No.");

        final EditText fieldInput = new EditText(this);
        fieldInput.setInputType(inputType);
        fieldInput.setHint(prompt);

        inputDialog.setView(fieldInput);
        inputDialog.setPositiveButton("OK", new DialogInterface.OnClickListener()
        {

            public void onClick(DialogInterface arg0, int arg1)
            {
                inputFromInputDialog = fieldInput.getText().toString();
                inputThread.notify();

            }
        });

        inputDialog.setNegativeButton("Cancel", new DialogInterface.OnClickListener()
        {

            public void onClick(DialogInterface arg0, int arg1)
            {
                inputFromInputDialog = null;
                inputThread.notify();
            }
        });

        inputDialog.show(); 
    }   
}

Answer 1

不不不!不要阻止UI线程.系统将引发"应用程序无响应"错误.此外,不要尝试从非UI线程与用户交互.

当用户单击"编辑"时,不要启动编辑方法.只需弹出一个对话框即可收集所需信息.添加DialogInterface.OnClickListener到肯定按钮并(现在掌握所需信息)从那里开始编辑方法.

有关更多信息,请参阅指南主题对话框.