这是我的代码如何将数据存储在sqlite数据库中。现在我希望数据库中的所有数据以其他活动中的卡形式显示，当我按下showdb按钮然后显示数据时。
public class ConfigureNode extends AppCompatActivity implements
LocationListener,
GoogleApiClient.ConnectionCallbacks,
GoogleApiClient.OnConnectionFailedListener {
private static final String TAG = "LocationActivity";
private static final long INTERVAL = 1000 * 10;
private static final long FASTEST_INTERVAL = 1000 * 5;
private SQLiteDatabase db;
Button btnFusedLocation, btnPushData;
TextView tvLocation;
EditText Latval, LongVal,NodeId;
LocationRequest mLocationRequest;
GoogleApiClient mGoogleApiClient;
Location mCurrentLocation;
String mLastUpdateTime;
public String DBPath;
public static String DBName = "sample";
public static final int version = '1';
public static Context currentContext;
protected void createLocationRequest() {
mLocationRequest = new LocationRequest();
mLocationRequest.setInterval(INTERVAL);
mLocationRequest.setFastestInterval(FASTEST_INTERVAL);
mLocationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
createDatabase();
Log.d(TAG, "onCreate ...............................");
//show error dialog if GoolglePlayServices not available
if (!isGooglePlayServicesAvailable()) {
finish();
}
createLocationRequest();
mGoogleApiClient = new GoogleApiClient.Builder(this)
.addApi(LocationServices.API)
.addConnectionCallbacks(this)
.addOnConnectionFailedListener(this)
.build();
setContentView(R.layout.activity_configure_node);
tvLocation = (TextView) findViewById(R.id.tvLocation);
btnFusedLocation = (Button) findViewById(R.id.btnShowLocation);
Latval = (EditText) findViewById(R.id.latVal);
LongVal = (EditText) findViewById(R.id.longVal);
NodeId=(EditText)findViewById(R.id.NodeId);
btnPushData = (Button) findViewById(R.id.btnPushLoc);
btnPushData.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
insertIntoDB();
}
});
btnFusedLocation.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
updateUI();
}
});
}
@Override
public void onStart() {
super.onStart();
Log.d(TAG, "onStart fired ..............");
mGoogleApiClient.connect();
}
@Override
public void onStop() {
super.onStop();
Log.d(TAG, "onStop fired ..............");
mGoogleApiClient.disconnect();
Log.d(TAG, "isConnected ...............: " + mGoogleApiClient.isConnected());
}
private boolean isGooglePlayServicesAvailable() {
int status = GooglePlayServicesUtil.isGooglePlayServicesAvailable(this);
if (ConnectionResult.SUCCESS == status) {
return true;
} else {
GooglePlayServicesUtil.getErrorDialog(status, this, 0).show();
return false;
}
}
@Override
public void onConnected(Bundle bundle) {
Log.d(TAG, "onConnected - isConnected ...............: " + mGoogleApiClient.isConnected());
startLocationUpdates();
}
protected void startLocationUpdates() {
if (ActivityCompat.checkSelfPermission(this, android.Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, android.Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
// TODO: Consider calling
// ActivityCompat#requestPermissions
// here to request the missing permissions, and then overriding
// public void onRequestPermissionsResult(int requestCode, String[] permissions,
// int[] grantResults)
// to handle the case where the user grants the permission. See the documentation
// for ActivityCompat#requestPermissions for more details.
return;
}
PendingResult<Status> pendingResult = LocationServices.FusedLocationApi.requestLocationUpdates(
mGoogleApiClient, mLocationRequest, (com.google.android.gms.location.LocationListener) this);
Log.d(TAG, "Location update started ..............: ");
}
@Override
public void onConnectionSuspended(int i) {
}
@Override
public void onConnectionFailed(ConnectionResult connectionResult) {
Log.d(TAG, "Connection failed: " + connectionResult.toString());
}
@Override
public void onLocationChanged(Location location) {
Log.d(TAG, "Firing onLocationChanged..............................................");
mCurrentLocation = location;
mLastUpdateTime = DateFormat.getTimeInstance().format(new Date());
updateUI();
}
private void updateUI() {
Log.d(TAG, "UI update initiated .............");
if (null != mCurrentLocation) {
String lat = String.valueOf(mCurrentLocation.getLatitude());
String lng = String.valueOf(mCurrentLocation.getLongitude());
tvLocation.setText("At Time: " + mLastUpdateTime + "\n" +
"Latitude: " + lat + "\n" +
"Longitude: " + lng + "\n" +
"Accuracy: " + mCurrentLocation.getAccuracy() + "\n" +
"Provider: " + mCurrentLocation.getProvider());
LongVal.setText(lng);
Latval.setText(lat);
} else {
Toast.makeText(ConfigureNode.this,"location not detected ",Toast.LENGTH_SHORT).show();
}
}
@Override
protected void onPause() {
super.onPause();
stopLocationUpdates();
}
protected void stopLocationUpdates() {
LocationServices.FusedLocationApi.removeLocationUpdates(
mGoogleApiClient, (LocationListener) this);
Log.d(TAG, "Location update stopped .......................");
}
@Override
public void onResume() {
super.onResume();
if (mGoogleApiClient.isConnected()) {
startLocationUpdates();
Log.d(TAG, "Location update resumed .....................");
}
}
protected void createDatabase(){
db=openOrCreateDatabase("PersonDB", Context.MODE_PRIVATE, null);
db.execSQL("CREATE TABLE IF NOT EXISTS persons(id INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL, name VARCHAR,address VARCHAR,NodeId VARCHAR);");
}
protected void insertIntoDB(){
String name = Latval.getText().toString().trim();
String add = LongVal.getText().toString().trim();
String Nodid=NodeId.getText().toString().trim();
if(name.equals("") || add.equals("")||Nodid.equals("")){
Toast.makeText(getApplicationContext(),"Please fill all fields", Toast.LENGTH_LONG).show();
return;
}
String query = "INSERT INTO persons (name,address,NodeId) VALUES('"+name+"', '"+add+"', '"+Nodid+"');";
db.execSQL(query);
Toast.makeText(getApplicationContext(),"Saved Successfully", Toast.LENGTH_LONG).show();
}
}
答案 0 :(得分：0)
我可以看到您已将添加数据添加到您的数据库中。您现在需要通过查询从数据库中检索数据。
想象一下，我在数据库中存储了一堆模板，然后想要在卡片或列表中显示所有这些。
我倾向于创建一个对象，例如Template.java。该对象将具有getter和setter方法。
然后我在数据库上执行查询，获取其中的所有数据，并将每个数据分配给这些Template对象。
然后我可以创建一个自定义列表视图，例如将它们显示在卡片列表中。要创建这个自定义列表，我给它一个数组，其中包含我从数据库中获取的所有Template对象，并在此自定义适配器类中设置值和样式。
以下是一些编码示例：
从数据库中获取并创建自定义列表：
public void populateListView() {
templates.clear();
final String query = "SELECT * FROM tableTemplates ";
Cursor c1 = db.selectQuery(query);
if (c1 != null && c1.getCount() != 0) {
if (c1.moveToFirst()) {
do {
template = new Template();
template.setTemplateName(c1.getString(c1
.getColumnIndex("templateName")));
template.setBuildingNumber(c1.getString(c1
.getColumnIndex("buildingNumber")));
template.setGroupNumber(c1.getString(c1
.getColumnIndex("groupNumber")));
template.setRemote(c1.getString(c1
.getColumnIndex("remote")));
template.setFrequency(c1.getString(c1
.getColumnIndex("frequency")));
templates.add(template);
} while (c1.moveToNext());
}
}
c1.close();
adapter = new TemplateCustomAdapter(
getApplicationContext(), templates);
presetList.setAdapter(adapter);
adapter.notifyDataSetChanged();
}
自定义列表适配器：
public class TemplateCustomAdapter extends BaseAdapter {
private Context context;
private ArrayList<Template> templateList;
public TemplateCustomAdapter(Context context, ArrayList<Template> list) {
this.context = context;
templateList = list;
}
@Override
public int getCount() {
return templateList.size();
}
@Override
public Object getItem(int position) {
return templateList.get(position);
}
@Override
public long getItemId(int position) {
return position;
}
/**
* Here we inflate our layout with the view row xml file.
* What the file does is set the look of each row of the list view.
* */
@Override
public View getView(int position, View convertView, ViewGroup arg2) {
final Template template = templateList.get(position);
if (convertView == null) {
LayoutInflater inflater = (LayoutInflater) context
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
convertView = inflater.inflate(R.layout.view_row, null);
}
/**
* Set the layout components with the object variable and return to the activity/fragment.
* */
final TextView templateName = (TextView) convertView.findViewById(R.id.name);
templateName.setText(template.getTemplateName());
return convertView;
}
}