我的 Android 应用程序中有一个运行良好的 ListActivity。 直到我决定使用加速度计添加滚动功能。
这是我的代码:
package be.pxl.minecraftguide;
import android.app.ListActivity;
import android.content.ContentResolver;
import android.database.Cursor;
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.os.Bundle;
import android.support.v4.widget.SimpleCursorAdapter;
import android.widget.ListView;
import be.pxl.minecraftguide.providers.RecipeCategoryProvider;
public class Crafting extends ListActivity implements SensorEventListener {
private SimpleCursorAdapter adapter;
private SensorManager sensorManager;
private Sensor acceleroMeter;
private float[] history = new float[2];
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.categorylist);
ContentResolver cr = getContentResolver();
Cursor cursor = cr.query(RecipeCategoryProvider.CONTENT_URI, null, null, null, null);
String[] from = {RecipeCategoryProvider.COL_CATID, RecipeCategoryProvider.COL_CATIMG, RecipeCategoryProvider.COL_CATDESC};
int[] to = { R.id.txtCatID, R.id.imgCatImage, R.id.txtCatDescription };
adapter = new SimpleCursorAdapter(getApplicationContext(), R.layout.categoryrow, cursor, from, to, 0);
/*SimpleCursorAdapter.ViewBinder viewBinder = new SimpleCursorAdapter.ViewBinder() {
@Override
public boolean setViewValue(View view, Cursor cursor, int arg2) {
if(view.getId() == R.id.imgCatImage) {
ImageView image = (ImageView)findViewById(R.id.imgCatImage);
image.setImageResource(R.drawable.ic_launcher);
}
return false;
}
};*/
setListAdapter(adapter);
//__________BRON/ http://stackoverflow.com/questions/18751878/android-using-the-accelerometer-to-create-a-simple-maraca-app_____________
sensorManager = (SensorManager) getSystemService(SENSOR_SERVICE);
acceleroMeter = sensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
sensorManager.registerListener(this, acceleroMeter, 1000000);
/*recipeListView.setOnClickListener(new OnItemClickListener(){
public void onItemClick(AdapterView<?> parent, View row,
int position, long id) {
TextView txtId = (TextView)row.findViewById(R.id.txtRecipeID);
int recipeID = Integer.parseInt(txtId.getText().toString());
String description = ((TextView)row.findViewById(R.id.txtRecipeDescription)).getText().toString();
// Launching new Activity on selecting single List Item
// Intent craftingDetailIntent = new Intent(getApplicationContext(), craftingdetail.class);
// sending data to new activity
//craftingDetailIntent.putExtra("Category", item);
//startActivity(craftingDetailIntent);
}
});*/
}
/*@Override
protected void onListItemClick(ListView l, View v, int position, long id) {
// TODO Auto-generated method stub
super.onListItemClick(l, v, position, id);
int recipeID = Integer.parseInt(v.getTag().toString());
}*/
@Override
protected void onPause() {
// TODO Auto-generated method stub
super.onPause();
sensorManager.unregisterListener(this); //De accelerometer afzetten
}
@Override
protected void onResume() {
// TODO Auto-generated method stub
super.onResume();
sensorManager.registerListener(this, acceleroMeter, SensorManager.SENSOR_DELAY_UI); //De accelerometer opnieuw starten
}
@Override
public void onAccuracyChanged(Sensor sensor, int accuracy) {
// TODO Auto-generated method stub
}
@Override
public void onSensorChanged(SensorEvent event) {
if (event.sensor.getType() == Sensor.TYPE_ACCELEROMETER) {
float xChange = history[0] - event.values[0];
float yChange = history[1] - event.values[1]; //Verschil tussen nieuwe en oude positie ophalen.
history[0] = event.values[0];
history[1] = event.values[1]; //Nieuwe waarden bewaren voor volgende event trigger
if (xChange > 2){
//Links
}
else if (xChange < -2){
//Rechts
}
if (yChange > 2){
getListView().smoothScrollBy(getListView().getHeight() * adapter.getCount(), 2000);
getListView().postDelayed(new Runnable() {
@Override
public void run() {
getListView().smoothScrollBy(0, 0); //Geanimeerd scrollen naar laatste positie
getListView().setSelection(adapter.getCount() - 1);
}
}, 1000);
}
else if (yChange < -2){
getListView().smoothScrollBy(getListView().getHeight() * adapter.getCount(), 2000);
getListView().postDelayed(new Runnable() {
@Override
public void run() {
getListView().smoothScrollBy(0, 0); //Geanimeerd scrollen naar eerste positie positie
getListView().setSelection(0);
}
}, 1000);
}
}
}
}
问题是，当我向上移动时，列表应该向下滚动并停留在底部。但是我的列表会向下滚动，然后偶尔会向上滚动。向下运动也是如此。
<?xml version="1.0" encoding="utf-8"?>
<ListView xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@android:id/list"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="@drawable/minecraft_portrait"
android:transcriptMode="alwaysScroll" >
</ListView>
并不太相关，但这是我的行 xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/recipeRow"
android:layout_width="match_parent"
android:layout_height="65sp"
android:background="@drawable/listview_selector" >
<TextView
android:id="@+id/txtCatID"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="5dp"
android:layout_marginTop="5dp"
android:textColor="@android:color/black" />
<ImageView
android:id="@+id/imgCatImage"
android:layout_width="wrap_content"
android:layout_height="55sp"
android:layout_centerVertical="true"
android:layout_alignParentLeft="true"
android:src="@drawable/ic_launcher"
android:contentDescription="@string/recipecategory" />
<TextView
android:id="@+id/txtCatDescription"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_centerVertical="true"
android:layout_toRightOf="@id/imgCatImage"
android:gravity="center"
android:background="#99FFFFFF"
android:textSize="20sp"
android:textColor="@android:color/black"
android:text="test" />
</RelativeLayout>
我该如何解决这个问题？
最佳答案
我一直在寻找使用传感器滚动 ListActivity 的相同解决方案(在 Google Glass 的上下文中)，而另一个答案对我不起作用(滚动不稳定)。
不过，我能够让另一个版本正常工作，仅基于 ListView(mList，在下面的示例中)。请注意，这还假设一次屏幕上的项目数量是固定的(因为所有 Glass 显示器的尺寸都相同)，但是可以更改此设置以检查屏幕上有多少项目以获得更通用的 Android 解决方案。此解决方案还使用 Sensor.TYPE_ROTATION_VECTOR ，它在支持的设备上进行一些传感器融合，因此输出噪音较小(导致不需要的上下移动较少)。
注册监听器:
mSensorManager = (SensorManager) mContext.getSystemService(Context.SENSOR_SERVICE);
mSensorManager.registerListener(this,
mSensorManager.getDefaultSensor(Sensor.TYPE_ROTATION_VECTOR),
SensorManager.SENSOR_DELAY_UI);
...这是 onSensorChanged() 方法:
@Override
public void onSensorChanged(SensorEvent event) {
if (mList == null) {
return;
}
if (event.sensor.getType() == Sensor.TYPE_ROTATION_VECTOR) {
SensorManager.getRotationMatrixFromVector(mRotationMatrix, event.values);
// Only uncomment the below two lines if you're running on Google Glass
//SensorManager.remapCoordinateSystem(mRotationMatrix, SensorManager.AXIS_X,
// SensorManager.AXIS_Z, mRotationMatrix);
SensorManager.getOrientation(mRotationMatrix, mOrientation);
mHeading = (float) Math.toDegrees(mOrientation[0]);
mPitch = (float) Math.toDegrees(mOrientation[1]);
float xDelta = history[0] - mHeading; // Currently unused
float yDelta = history[1] - mPitch;
history[0] = mHeading;
history[1] = mPitch;
float Y_DELTA_THRESHOLD = 0.10f;
//Log.d(TAG, "Y Delta = " + yDelta);
int scrollHeight = mList.getHeight()
/ 19; // 4 items per page, scroll almost 1/5 an item
//Log.d(TAG, "ScrollHeight = " + scrollHeight);
if (yDelta > Y_DELTA_THRESHOLD) {
//Log.d(TAG, "Detected change in pitch up...");
mList.smoothScrollBy(-scrollHeight, 0);
} else if (yDelta < -Y_DELTA_THRESHOLD) {
//Log.d(TAG, "Detected change in pitch down...");
mList.smoothScrollBy(scrollHeight, 0);
}
}
}
其他详细信息在这个答案中: https://stackoverflow.com/a/23298377/937715
有关重新映射传感器坐标系以处理 Android 设备上所有可能的方向变化的代码，请参阅: https://stackoverflow.com/a/22138449/937715
关于Android listactivity 滚动与加速度计问题，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/19540828/