android 学习

Handler 使用

Bundle bundleData = Algorithm(location);
  if (bundleData != null) {
    LocationHandler locationHandler = new LocationHandler(MapActivity.this);
    Message locationMsg = locationHandler.obtainMessage();
    bundleData.putParcelable("location", location);
    locationMsg.setData(bundleData);
    locationHandler.sendMessage(locationMsg);
}
    ```

## Handler 弱引用处理内存泄漏
```java
  public static class LocationHandler extends Handler {
    WeakReference<MapActivity> mActivity;
    LocationHandler(MapActivity activity) {
        mActivity = new WeakReference<>(activity);
    }
    @Override
    public void handleMessage(Message msg) {
        MapActivity activity = mActivity.get();
        if (activity != null) {
            // TODO: 2019年4月17日
        }
    }
}