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Question

我正在制作一个android应用程序，我在代码的这一部分中感到困惑。在上一个类中，我集成了蓝牙并调用了startApp。我想在调用startApp时在主页上显示这些按钮。据我所知，这就是我该怎么做的？为什么我不能这么做？当我尝试这样做时，eclipse不允许我这样做。我如何更改代码，以便可以设置如下所示的主菜单开始页？

谢谢！！

main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:background="@color/background"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:padding="85dip" 
    android:orientation="horizontal">
    <LinearLayout 
        android:layout_width="wrap_content"
        android:layout_height="fill_parent"
        android:layout_gravity="center" android:orientation="vertical">
        <TextView 
            android:text="@string/mainTitle"
            android:layout_width="fill_parent" 
            android:layout_height="wrap_content" 
            android:layout_gravity="center"
            android:layout_marginBottom="25dip"
            android:textSize="24.5sp"/>


        <!-- Patient Option -->
        <Button android:layout_width="fill_parent"
                android:layout_height="wrap_content" 
                android:layout_weight="1"
            android:text="@string/patientButton"
            android:id="@+id/patientButton">
        </Button>

        <!-- Doctor Option -->
        <Button android:layout_width="fill_parent"
            android:layout_height="wrap_content" 
            android:text="@string/doctorButton"
            android:layout_weight="1"
            android:id="@+id/doctorButton">
        </Button>

        <!-- Exit Mode -->
        <Button android:text="@string/exit" 

         android:layout_weight="1"
         android:id="@+id/exit" 
         android:layout_width="fill_parent" 
         android:layout_height="wrap_content"></Button>

         <!-- About Mode -->
        <Button android:text="@string/aboutButton" 

         android:layout_weight="1"
         android:id="@+id/aboutButton" 
         android:layout_width="fill_parent" 
         android:layout_height="wrap_content"></Button>

    </LinearLayout>



</LinearLayout>



    package com.joshi.remotedoc;

import com.joshi.remotedoc.DeviceList;

import android.app.Activity;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.content.Intent;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.TextView;
import android.widget.Toast;


public class Remote_DocActivity extends Activity implements OnClickListener {    
    /** Called when the activity is first created. */
    //private static final String TAG = "Remote_Doc";
    private static final String TAG = "BluetoothChat";
    private static final boolean D = true;
    private static final int REQUEST_CONNECT_DEVICE_SECURE = 1;
    private static final int REQUEST_CONNECT_DEVICE_INSECURE = 2;
    private static final int REQUEST_ENABLE_BT = 3;
    private BluetoothAdapter mBluetoothAdapter = null;
    private String mConnectedDeviceName = null;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        if(D) Log.e(TAG, "+++ ON CREATE +++");
        setContentView(R.layout.main);



        mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
        if (mBluetoothAdapter == null) {
            Toast.makeText(this, "Bluetooth is not available", Toast.LENGTH_LONG).show();
            finish();
            return;
            }        
    }

    @Override
    public void onStart() {
        super.onStart();
        if(D) Log.e(TAG, "++ ON START ++");
        // If BT is not on, request that it be enabled.
        if (!mBluetoothAdapter.isEnabled()) {
            Intent enableIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
            startActivityForResult(enableIntent, REQUEST_ENABLE_BT);
            } 
        else {
            startApp();
            }
        }

    private void ensureDiscoverable() {
        if(D) Log.d(TAG, "ensure discoverable");
        if (mBluetoothAdapter.getScanMode() !=
            BluetoothAdapter.SCAN_MODE_CONNECTABLE_DISCOVERABLE) {
            Intent discoverableIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_DISCOVERABLE);
            discoverableIntent.putExtra(BluetoothAdapter.EXTRA_DISCOVERABLE_DURATION, 300);
            startActivity(discoverableIntent);
            }
        }
    private void startApp(){

        View Patient_Button = findViewById(R.id.patientButton);
        Patient_Button.setOnClickListener(this);
        Patient_Button.setOnClickListener(new OnClickListener() {
            public void onClick(View v) {
                Intent b = new Intent(this, Detailed_ModeActivity.class);
                startActivity(b);
                break;
                }
            }
        );
        View Doctor_Button = findViewById(R.id.doctorButton);
        Doctor_Button.setOnClickListener(this);
        View About_Option = findViewById(R.id.aboutButton);
        About_Option.setOnClickListener(this);
        View Exit_Option = findViewById(R.id.exit);
        Exit_Option.setOnClickListener(this);



    }

    /*private final Handler mHandler = new Handler() {
        @Override
        public void handleData(Data data) {

        }
        }*/
    private void connectDevice(Intent data, boolean secure) {
        // Get the device MAC address
        String address = data.getExtras()
        .getString(DeviceList.EXTRA_DEVICE_ADDRESS);
        // Get the BluetoothDevice object
        BluetoothDevice device = mBluetoothAdapter.getRemoteDevice(address);
        // Attempt to connect to the device
        //mChatService.connect(device, secure);
        }

    public void onClick(View v) {
        switch (v.getId()) {
        case R.id.patientButton:
            Intent b = new Intent(this, Detailed_ModeActivity.class);
            startActivity(b);
            break;
        case R.id.doctorButton:
            Intent a = new Intent(this, Detailed_ModeActivity.class);
            startActivity(a);
            break;
        case R.id.aboutButton:
            Intent i = new Intent(this, About.class);
            startActivity(i);
            break;
        case R.id.exit:
            finish();
            break;
        }

    }   


}

Answer 1

而不是：

Intent b = new Intent(this, Detailed_ModeActivity.class);

试试这个：

Intent b = new Intent(getApplicationContext(), Detailed_ModeActivity.class);

Answer 2

我有几点可能会有帮助：

1. 阅读Eclipse给你的错误是一个很大的优势，你的许多问题都会通过阅读它来解决。
2. 是你在活动中的startApp方法吗？如果没有，你就不能在那里调用findViewById，因为这是Activity对象的一个方法。
3. 你的代码中有很多.setOnClickListener(this);，你的类实现OnClickListener了吗？如果您希望将其设置为视图

的OnClickListener，则必须进行此设置