对于Android Studio来说，我是一个非常新的但是已经设法将2个在单独的应用程序下运行良好的活动组合在一起，但是当加入时，MainActivity使用{AddressActivity调用Intent时崩溃了1}}和startActivity。
还有另一个可能相关或不相关的问题。安装应用程序时，没有请求权限。
这是我的代码：
的AndroidManifest.xml
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_COURSE_LOCATION" />
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:supportsRtl="true"
android:theme="@style/AppTheme">
<activity
android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name=".AddressActivity"
android:label="login">
</activity>
</application>
MainActivity.class
package crproductionsptyltd.login;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import static crproductionsptyltd.login.R.id.driverid;
import static crproductionsptyltd.login.R.id.login;
public class MainActivity extends Activity {
EditText driverid;
Button btnOk;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);
// find View-elements
btnOk = (Button) findViewById(login);
// btnOk.setOnClickListener(this)
// create click listener
View.OnClickListener oclBtnOk = new View.OnClickListener() {
@Override
public void onClick(View v) {
// change text of the TextView (tvOut)
btnOk.setText("Logging IN.....");
Intent i = new Intent(MainActivity.this, AddressActivity.class);
i.putExtra("driver_id", driverid.getText().toString());
startActivity(i);
};
};
// assign click listener to the OK button (btnOK)
btnOk.setOnClickListener(oclBtnOk);
// startActivity(new Intent(MainActivity.this, AddressActivity.class));
// Intent i = new Intent(MainActivity.this, NewActivity.class);//
// startActivity(i);
};
}
AddressActivity.class
package crproductionsptyltd.login;
import java.io.IOException;
import java.net.URL;
import java.net.URLConnection;
import java.util.List;
import java.util.Locale;
import android.app.Activity;
import android.content.Context;
import android.location.Address;
import android.location.Geocoder;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;
import android.content.Intent;
public class AddressActivity extends Activity {
/**
* Called when the activity is first created.
*/
String lat = "", lon = "";
TextView tvView;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_gps);
tvView = (TextView) findViewById(R.id.tvView);
Intent intent = getIntent();
String driverid = intent.getStringExtra("driver_id");
tvView.setText("Your Driver ID is: " + driverid);
Button btnLocation = (Button) findViewById(R.id.btnLocation);
btnLocation.setOnClickListener(new OnClickListener() {
public void onClick(View arg0) {
// Acquire a reference to the system Location Manager
LocationManager locationManager = (LocationManager) AddressActivity.this.getSystemService(Context.LOCATION_SERVICE);
// Define a listener that responds to location updates
LocationListener locationListener = new LocationListener() {
public void onLocationChanged(Location location) {
// Called when a new location is found by the network location provider.
lat = Double.toString(location.getLatitude());
lon = Double.toString(location.getLongitude());
TextView tv = (TextView) findViewById(R.id.txtLoc);
tv.setText("Your Location is:" + lat + "--" + lon);
}
public void onStatusChanged(String provider, int status, Bundle extras) {
}
public void onProviderEnabled(String provider) {
}
public void onProviderDisabled(String provider) {
}
};
// Register the listener with the Location Manager to receive location updates
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, locationListener);
}
});
Button btnSend = (Button) findViewById(R.id.btnSend);
btnSend.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
postData(lat, lon);
}
});
Button btnAdd = (Button) findViewById(R.id.btnAddress);
btnAdd.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
TextView tv = (TextView) findViewById(R.id.txtAddress);
tv.setText(GetAddress(lat, lon));
}
});
}
public void postData(String la, String lo) {
//URL url = new URL("https://www.autoflora.net/driver/gps.php?Driver_ID=877&latlong=" + lat + "*" + lon);
int TIMEOUT_VALUE = 15000;
try{
URL myUrl = new URL("https://www.autoflora.net/driver/gps.php?Driver_ID=877&latlong=" + lat + "*" + lon);
URLConnection connection = myUrl.openConnection();
connection.setConnectTimeout(TIMEOUT_VALUE);
connection.connect();
} catch (Exception e) {
}
}
public String GetAddress(String lat, String lon)
{
Geocoder geocoder = new Geocoder(this, Locale.ENGLISH);
String ret = "";
try {
List<Address> addresses = geocoder.getFromLocation(Double.parseDouble(lat), Double.parseDouble(lon), 1);
if(addresses != null) {
Address returnedAddress = addresses.get(0);
StringBuilder strReturnedAddress = new StringBuilder("Address:\n");
for(int i=0; i<returnedAddress.getMaxAddressLineIndex(); i++) {
strReturnedAddress.append(returnedAddress.getAddressLine(i)).append("\n");
}
ret = strReturnedAddress.toString();
}
else{
ret = "No Address returned!";
}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
ret = "Can't get Address!";
}
return ret;
}
}
activity_login.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center_horizontal"
android:orientation="vertical"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="crproductionsptyltd.login.LoginActivity">
<!-- Login progress -->
<ProgressBar
android:id="@+id/login_progress"
style="?android:attr/progressBarStyleLarge"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="8dp"
android:visibility="gone" />
<ScrollView
android:id="@+id/login_form"
android:layout_width="match_parent"
android:layout_height="match_parent">
<LinearLayout
android:id="@+id/email_login_form"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<android.support.design.widget.TextInputLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
<AutoCompleteTextView
android:id="@+id/driverid"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="Driver ID"
android:inputType="textEmailAddress"
android:maxLines="1"
android:singleLine="true" />
</android.support.design.widget.TextInputLayout>
<android.support.design.widget.TextInputLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
</android.support.design.widget.TextInputLayout>
<Button
android:id="@+id/login"
style="?android:textAppearanceSmall"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="16dp"
android:text="Login"
android:textStyle="bold"
android:onClick="checkDriver" />
</LinearLayout>
</ScrollView>
</LinearLayout>
activity_gps.class
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<TextView
android:id="@+id/txtLoc"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="TextView" />
<TextView
android:id="@+id/tvView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:layout_marginTop="20dp"
android:textSize="20sp">
</TextView>
<Button
android:id="@+id/btnLocation"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Get my Location" />
<Button
android:id="@+id/btnSend"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Send Location" />
<Button
android:id="@+id/btnAddress"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Try Get Street Address" />
<TextView
android:id="@+id/txtAddress"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Medium Text"
android:textAppearance="?android:attr/textAppearanceMedium" />
</LinearLayout>
答案 0 :(得分：0)
我认为，要使用android.support.design.widget.TextInputLayout 你应该使用这些依赖
compile 'com.android.support:appcompat-v7:22.2.0'
compile 'com.android.support:design:22.2.0'
＆安培;还请更正
btnOk = (Button) findViewById(R.id.login); //wrongly added
driverid = (EditText) findViewById(R.id.driverid); // not added
答案 1 :(得分：0)
根据您的代码，应用会在此处崩溃：i.putExtra("driver_id", driverid.getText().toString())，从而产生NullPointerException。它崩溃是因为你没有在EditText driverid;中对onCreate进行初始化，因此，当使用未初始化时，它会抛出异常。
要解决此问题，您必须更新onCreate中的字段：
driverid = (EditText) findViewById(driverid);