我正在使用Android Studio上的应用程序，当我按下按钮时，会给我wifi扫描的结果！ 如果我单独测试代码（只有部分“wifi扫描”）它可以工作......但是当我把它放在完整的应用程序中时，应用程序崩溃了！ 为什么？ 我发布了我的代码：
// MAIN
package com.example.pc1.tesiprova;
import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
public class MainActivity extends AppCompatActivity
{
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//CERCO GLI ELEMENTI BUTTON E BUTTON2
Button OutDoor = (Button) findViewById(R.id.button);
Button InDoor = (Button) findViewById(R.id.button2);
//CLICCANDO SU BUTTON FACCIO APRIRE UNA NUOVA ACTIVITY
OutDoor.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View arg0) {
//DEFINISCO L'INTENZIONE DI APRIRE UNA NUOVA ACTIVITY
Intent openActivityO=new Intent(MainActivity.this,ActivityO.class);
//APRO L'ACTIVITY ACTIVITYO.JAVA
startActivity(openActivityO);
}
});
//CLICCANDO SU BUTTON2 FACCIO APRIRE UNA NUOVA ACTIVITY
InDoor.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View arg0) {
Intent openActivityI=new Intent(MainActivity.this,ActivityI.class);
startActivity(openActivityI);
}
});
}
// ACTIVITYO（包含wifi扫描！）
package com.example.pc1.tesiprova;
import android.content.Context;
import android.net.wifi.ScanResult;
import android.net.wifi.WifiManager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.TextView;
import java.util.List;
public class ActivityO extends AppCompatActivity {
public WifiManager wifi;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_o);
TextView text1 = (TextView)findViewById(R.id.textView);
TextView text2 = (TextView)findViewById(R.id.textView2);
TextView text3 = (TextView)findViewById(R.id.textView3);
wifi=(WifiManager)getSystemService(Context.WIFI_SERVICE);
for(int i=0;i<5;i++);
wifi.startScan();
try{
text1.setText("Sto cercando");
Thread.sleep(3333);
}
catch(InterruptedException e)
{
e.printStackTrace();
}
List<ScanResult> results = wifi.getScanResults();
String ssid1= results.get(0).SSID;
String ssid2= results.get(1).SSID;
String ssid3= results.get(2).SSID;
Integer rssi1= results.get(0).level;
Integer rssi2= results.get(1).level;
Integer rssi3= results.get(2).level;
text1.setText(ssid1+rssi1);
text2.setText(ssid2+rssi2);
text3.setText(ssid3+rssi3);
错误是：
10-23 08:30:04.257 2230-2230/com.example.pc1.tesiprova I/art﹕ Not late-enabling -Xcheck:jni (already on)
10-23 08:30:04.257 2230-2230/com.example.pc1.tesiprova I/art﹕ Late-enabling JIT
10-23 08:30:04.259 2230-2230/com.example.pc1.tesiprova I/art﹕ JIT created with code_cache_capacity=2MB compile_threshold=1000
10-23 08:30:04.867 2230-2230/com.example.pc1.tesiprova W/System﹕ ClassLoader referenced unknown path: /data/app/com.example.pc1.tesiprova-1/lib/x86
10-23 08:30:05.276 2230-2252/com.example.pc1.tesiprova D/OpenGLRenderer﹕ Use EGL_SWAP_BEHAVIOR_PRESERVED: true
10-23 08:30:05.286 2230-2230/com.example.pc1.tesiprova D/﹕ HostConnection::get() New Host Connection established 0xac07fda0, tid 2230
10-23 08:30:05.459 2230-2252/com.example.pc1.tesiprova D/﹕ HostConnection::get() New Host Connection established 0xac07feb0, tid 2252
10-23 08:30:05.507 2230-2252/com.example.pc1.tesiprova I/OpenGLRenderer﹕ Initialized EGL, version 1.4
10-23 08:30:05.576 2230-2252/com.example.pc1.tesiprova W/EGL_emulation﹕ eglSurfaceAttrib not implemented
10-23 08:30:05.576 2230-2252/com.example.pc1.tesiprova W/OpenGLRenderer﹕ Failed to set EGL_SWAP_BEHAVIOR on surface 0xac130fc0, error=EGL_SUCCESS
10-23 08:31:14.500 2230-2252/com.example.pc1.tesiprova W/EGL_emulation﹕ eglSurfaceAttrib not implemented
10-23 08:31:14.500 2230-2252/com.example.pc1.tesiprova W/OpenGLRenderer﹕ Failed to set EGL_SWAP_BEHAVIOR on surface 0xac13f560, error=EGL_SUCCESS
10-23 08:31:14.812 2230-2252/com.example.pc1.tesiprova E/Surface﹕ getSlotFromBufferLocked: unknown buffer: 0xac0763b0
10-23 08:31:14.819 2230-2252/com.example.pc1.tesiprova D/OpenGLRenderer﹕ endAllStagingAnimators on 0xa42e1280 (RippleDrawable) with handle 0xac12fbd0
10-23 08:31:16.517 2230-2252/com.example.pc1.tesiprova W/EGL_emulation﹕ eglSurfaceAttrib not implemented
10-23 08:31:16.517 2230-2252/com.example.pc1.tesiprova W/OpenGLRenderer﹕ Failed to set EGL_SWAP_BEHAVIOR on surface 0xad9c7840, error=EGL_SUCCESS
10-23 08:31:17.043 2230-2230/com.example.pc1.tesiprova I/Choreographer﹕ Skipped 30 frames! The application may be doing too much work on its main thread.
10-23 08:31:17.119 2230-2252/com.example.pc1.tesiprova E/Surface﹕ getSlotFromBufferLocked: unknown buffer: 0xac076c00
10-23 08:31:18.646 2230-2242/com.example.pc1.tesiprova I/art﹕ Background sticky concurrent mark sweep GC freed 9604(599KB) AllocSpace objects, 0(0B) LOS objects, 53% free, 1148KB/2MB, paused 1.649ms total 139.305ms
10-23 08:31:18.671 2230-2242/com.example.pc1.tesiprova W/art﹕ Suspending all threads took: 24.989ms
10-23 08:31:22.070 2230-2230/com.example.pc1.tesiprova D/AndroidRuntime﹕ Shutting down VM
--------- beginning of crash
10-23 08:31:22.093 2230-2230/com.example.pc1.tesiprova E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.example.pc1.tesiprova, PID: 2230
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.pc1.tesiprova/com.example.pc1.tesiprova.ActivityO}: java.lang.SecurityException: Need ACCESS_COARSE_LOCATION or ACCESS_FINE_LOCATION permission to get scan results
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2416)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476)
at android.app.ActivityThread.-wrap11(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5417)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
Caused by: java.lang.SecurityException: Need ACCESS_COARSE_LOCATION or ACCESS_FINE_LOCATION permission to get scan results
at android.os.Parcel.readException(Parcel.java:1599)
at android.os.Parcel.readException(Parcel.java:1552)
at android.net.wifi.IWifiManager$Stub$Proxy.getScanResults(IWifiManager.java:1066)
at android.net.wifi.WifiManager.getScanResults(WifiManager.java:1311)
at com.example.pc1.tesiprova.ActivityO.onCreate(ActivityO.java:44)
at android.app.Activity.performCreate(Activity.java:6237)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1107)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2369)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476)
at android.app.ActivityThread.-wrap11(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5417)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
10-23 08:31:24.168 2230-2230/? I/Process﹕ Sending signal. PID: 2230 SIG: 9
我使用了这些权限：
<uses-permission android:name="android.permission.CHANGE_WIFI_STATE"/>
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE"/>
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/>
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.INTERNET" />
非常感谢!!!!
答案 0 :(得分：5)
您可能正在Android 6.0上测试应用程序（例如在模拟器中）。在这种情况下，您需要在运行时请求权限，仅在清单中声明它是不够的。
您需要检查是否已授予权限（这不是复制粘贴代码，您需要根据需要进行调整）：
if (ContextCompat.checkSelfPermission(mContext, Manifest.permission.ACCESS_COARSE_LOCATION))
== PackageManager.PERMISSION_GRANTED) {
//your code that requires permission
}
要获得许可，您需要使用此代码：
ActivityCompat.requestPermissions(activity, new String[] { Manifest.permission.ACCESS_COARSE_LOCATION },
REQUEST_CODE);
有关详细信息，请查看开发人员指南：http://developer.android.com/training/permissions/requesting.html
答案 1 :(得分：1)
请在清单中添加 ACCESS_FINE_LOCATION 权限，然后重试。
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>