Question

我想在webview加载特殊网址时激活传感器，所以我在webview定义中使用了sensorManager.registerListener：

@Override
public boolean shouldOverrideUrlLoading(WebView view, String url) {
    if (url.contains("compass")){
        sensorManager.registerListener(view.getContext().getApplicationContext(), compass, SensorManager.SENSOR_DELAY_NORMAL);
    }
}

很遗憾，view.getContext().getApplicationContext()无法正常工作。在这里获取上下文的标准方法是什么？

Answer 1

private Context context;

public Yourclassname(Context context) {//constructor
this.context = context;

在代码中使用该上下文

SensorManager mSensorMgr = (SensorManager) 
context.getSystemService(Context.SENSOR_SERVICE);

@Override
public boolean shouldOverrideUrlLoading(WebView view, String url) {
if (url.contains("compass")){

sensorManager.registerListener(context, 
compass, SensorManager.SENSOR_DELAY_NORMAL);
 }
}

//根据您的要求使用此内容或上下文

Answer 2

在MainActivity.java中添加以下代码

public class MainActivity extends AppCompatActivity {
public static MainActivity context;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        context = this;
    }
    public static MainActivity getInstance()
    {
        return context;
    }

}

通过调用此方法来使用此上下文

 @Override
    public boolean shouldOverrideUrlLoading(WebView view, String url) {
        if (url.contains("compass")){
            sensorManager.registerListener(MainActivity.getInstance(), compass, SensorManager.SENSOR_DELAY_NORMAL);
        }
    }

如何在WebView定义中获取上下文？

2 个答案: