我的 android 应用程序中有一个 ListActivity 可以完美运行。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，然后偶尔会备份。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>
并不是很相关，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>
我怎样才能解决这个问题？