我目前正在为学校做项目。到目前为止，一切都很顺利，直到我实施了HoloColorPicker。当我将colorpicker.addSaturationBar(saturationbar)添加到onCreate中的Mainactivity函数时，应用程序无法启动。
错误：
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.christian.rapid_charge_quad_05/com.example.christian.rapid_charge_quad_05.MainActivity}: java.lang.NullPointerException
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2110)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2135)
at android.app.ActivityThread.access$700(ActivityThread.java:140)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1237)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:4921)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1027)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:794)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
at com.example.christian.rapid_charge_quad_05.MainActivity.onCreate(MainActivity.java:78)
at android.app.Activity.performCreate(Activity.java:5206)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1094)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2074)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2135)
at android.app.ActivityThread.access$700(ActivityThread.java:140)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1237)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:4921)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1027)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:794)
at dalvik.system.NativeStart.main(Native Method) r code here
MainActivity：
package com.example.christian.rapid_charge_quad_05;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothSocket;
import android.content.Intent;
import android.os.Bundle;
import android.os.Handler;
import android.support.design.widget.NavigationView;
import android.support.v4.app.FragmentManager;
import android.support.v4.view.GravityCompat;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.ProgressBar;
import android.widget.TextView;
import android.widget.Toast;
import com.larswerkman.holocolorpicker.ColorPicker;
import com.larswerkman.holocolorpicker.SaturationBar;
import com.larswerkman.holocolorpicker.ValueBar;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.UUID;
import fragments.akku_fragment;
import fragments.beleuchtung_fragment;
import fragments.kamera_fragment;
import fragments.karte_fragement;
public class MainActivity extends AppCompatActivity
implements NavigationView.OnNavigationItemSelectedListener, ColorPicker.OnColorChangedListener {
private static String address = "98:D3:31:40:4D:A9";
private static final UUID MY_UUID = UUID.fromString("00001101-0000-1000-8000-00805F9B34FB");
final int handlerState = 0;
private static String TAG;
private static final int REQUEST_ENABLE_BT = 1;
private BluetoothAdapter btAdapter = null;
private BluetoothSocket btSocket = null;
private ConnectedThread mConnectedThread;
private StringBuilder recDataString = new StringBuilder();
Handler bluetoothIn;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//Navigation menu
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
//Navigation menu
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
drawer.setDrawerListener(toggle);
toggle.syncState();
NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
navigationView.setNavigationItemSelectedListener(this);
//Fragment Manager
FragmentManager fragmentManager = getSupportFragmentManager();
fragmentManager.beginTransaction().replace(R.id.content_main, new akku_fragment()).commit();
//Colorpicker
ColorPicker colorPicker = (ColorPicker)findViewById(R.id.picker);
SaturationBar saturationBar = (SaturationBar)findViewById(R.id.saturationbar);
colorPicker.addSaturationBar(saturationBar);
//Bluetooth
btAdapter = BluetoothAdapter.getDefaultAdapter(); //Check if Bluetooth is supported on the device
checkBTState(); //Go into subroutine checkBTState
Toast.makeText(getApplicationContext(), "Online", Toast.LENGTH_SHORT).show();
bluetoothIn = new Handler() {
public void handleMessage(android.os.Message msg) {
if (msg.what == handlerState) { //if message is what we want
String readMessage = (String) msg.obj; // msg.arg1 = bytes from connect thread
recDataString.append(readMessage); //keep appending to string until ~
Toast.makeText(getApplicationContext(), "empfange", Toast.LENGTH_LONG).show();
int endOfLineIndex = recDataString.indexOf("#"); // determine the end-of-line
if (endOfLineIndex > 0) {
String dataInPrint = recDataString.substring(0, endOfLineIndex); // extract string
int dataLength = dataInPrint.length();
String sensor0 = recDataString.substring(0, 3); //get sensor value from string between indices 1-5
TextView empfangen = (TextView) findViewById(R.id.text_empfangen);
empfangen.setText(sensor0 + " " + dataLength );
TextView percent = (TextView)findViewById(R.id.compliance_percentage);
percent.setText(sensor0 + "%");
try{
int Akkustand = Integer.valueOf(sensor0);
ProgressBar progressBar = (ProgressBar)findViewById(R.id.circle_progress_bar);
progressBar.setProgress(Akkustand);
}catch (NumberFormatException nfm){
Toast.makeText(getApplicationContext(), "Kann nicht konvertieren", Toast.LENGTH_LONG).show();
}
recDataString.delete(0, recDataString.length()); //clear all string data
// strIncom =" ";
dataInPrint = " ";
}
else{
Toast.makeText(getApplicationContext(), "Text kleiner als 0.", Toast.LENGTH_LONG).show();
}
}else{
Toast.makeText(getApplicationContext(), "nicht was wir wollen", Toast.LENGTH_LONG).show();
}
}
};
//Colorpicker
// ColorPicker picker = (ColorPicker)findViewById(R.id.picker);
// SVBar svBar = (SVBar) findViewById(R.id.svbar);
// OpacityBar opacityBar = (OpacityBar) findViewById(R.id.opacitybar);
// SaturationBar saturationBar = (SaturationBar)findViewById(R.id.saturationbar);
// ValueBar valueBar = (ValueBar)findViewById(R.id.valuebar);
// picker.addSVBar(svBar);
// picker.addOpacityBar(opacityBar);
// picker.getColor();
/* picker.addValueBar(valueBar);
//To get the color
picker.getColor();
//To set the old selected color u can do it like this
picker.setOldCenterColor(picker.getColor());
// adds listener to the colorpicker which is implemented
//in the activity
picker.setOnColorChangedListener(this);
//to turn of showing the old color
picker.setShowOldCenterColor(false);
//adding onChangeListeners to bars
// opacitybar.setOnOpacityChangeListener(new OnOpacityChangeListener)
// valuebar.setOnValueChangeListener(new NumberPicker.OnValueChangeListener …)
// saturationBar.setOnSaturationChangeListener(new OnSaturationChangeListener …)
*/
}
@Override
public void onBackPressed() {
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
if (drawer.isDrawerOpen(GravityCompat.START)) {
drawer.closeDrawer(GravityCompat.START);
} else {
super.onBackPressed();
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
//create device and set the MAC address
BluetoothDevice device = btAdapter.getRemoteDevice(address);
try {
btSocket = device.createRfcommSocketToServiceRecord(MY_UUID);
Toast.makeText(getBaseContext(), "Socket creation complete", Toast.LENGTH_LONG).show();
} catch (IOException e) {
Toast.makeText(getBaseContext(), "Socket creation failed", Toast.LENGTH_LONG).show();
Log.d(TAG, "...Cant create BT Socket...");
}
// Establish the Bluetooth socket connection.
try {
btSocket.connect();
Toast.makeText(getBaseContext(), "Connected to Device", Toast.LENGTH_LONG).show();
Log.d(TAG, "...Connected to Device...");
TextView online = (TextView)findViewById(R.id.textview_online);
online.setText("Online");
} catch (IOException e) {
try {
Toast.makeText(getBaseContext(), "BT socket close", Toast.LENGTH_LONG).show();
btSocket.close();
} catch (IOException e2) {
//insert code to deal with this
}
}
mConnectedThread = new ConnectedThread(btSocket);
mConnectedThread.start();
Toast.makeText(getApplicationContext(), "Auf Verbinden geklickt!", Toast.LENGTH_SHORT).show();
//I send a character when resuming.beginning transmission to check device is connected
//If it is not an exception will be thrown in the write method and finish() will be called
return true;
}
return super.onOptionsItemSelected(item);
}
@SuppressWarnings("StatementWithEmptyBody")
@Override
public boolean onNavigationItemSelected(MenuItem item) {
// Handle navigation view item clicks here.
int id = item.getItemId();
FragmentManager fragmentManager = getSupportFragmentManager();
fragmentManager.beginTransaction().replace(R.id.content_main, new akku_fragment()).commit();
if (id == R.id.nav_kamera) {
fragmentManager.beginTransaction().replace(R.id.content_main, new kamera_fragment()).commit();
} else if (id == R.id.nav_karte) {
fragmentManager.beginTransaction().replace(R.id.content_main, new karte_fragement()).commit();
} else if (id == R.id.nav_akku) {
fragmentManager.beginTransaction().replace(R.id.content_main, new akku_fragment()).commit();
} else if (id == R.id.nav_beleuchtung) {
fragmentManager.beginTransaction().replace(R.id.content_main, new beleuchtung_fragment()).commit();
}
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
drawer.closeDrawer(GravityCompat.START);
return true;
}
private void checkBTState() {
// Check for Bluetooth support and then check to make sure it is turned on
// Emulator doesn't support Bluetooth and will return null
if(btAdapter==null) {
Toast.makeText(getApplicationContext(), "Bluetooth Not supported.", Toast.LENGTH_SHORT).show();
Log.d(TAG, "...Bluetooth Not supported...");
} else {
if (btAdapter.isEnabled()) {
Log.d(TAG, "...Bluetooth is enabled...");
} else {
//Ask user to turn on Bluetooth
Intent enableBtIntent = new Intent(btAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(enableBtIntent, REQUEST_ENABLE_BT);
}
}
}
@Override
public void onColorChanged(int color) {
}
private class ConnectedThread extends Thread {
private final InputStream mmInStream;
private final OutputStream mmOutStream;
//creation of the connect thread
public ConnectedThread(BluetoothSocket socket) {
InputStream tmpIn = null;
OutputStream tmpOut = null;
try {
//Create I/O streams for connection
tmpIn = socket.getInputStream();
tmpOut = socket.getOutputStream();
Log.d(TAG, "...Create I/O Streams...");
} catch (IOException e) {
}
mmInStream = tmpIn;
mmOutStream = tmpOut;
}
public void run() {
byte[] buffer = new byte[256];
int bytes;
// Keep looping to listen for received messages
while (true) {
try {
bytes = mmInStream.read(buffer); //read bytes from input buffer
String readMessage = new String(buffer, 0, bytes);
// Send the obtained bytes to the UI Activity via handler
bluetoothIn.obtainMessage(handlerState, bytes, -1, readMessage).sendToTarget();
} catch (IOException e) {
break;
}
}
}
//write method
public void write(String input) {
byte[] msgBuffer = input.getBytes(); //converts entered String into bytes
try {
mmOutStream.write(msgBuffer); //write bytes over BT connection via outstream
} catch (IOException e) {
//if you cannot write, close the application
Toast.makeText(getBaseContext(), "Connection Failure", Toast.LENGTH_LONG).show();
finish();
}
}
}
}
Fragment_beleuchtung：
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent" android:layout_height="match_parent">
<com.larswerkman.holocolorpicker.ColorPicker
android:id="@+id/picker"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:layout_marginTop="50dp" />
<com.larswerkman.holocolorpicker.SaturationBar
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_below="@+id/picker"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:id="@+id/saturationbar"/>
</RelativeLayout>
答案 0 :(得分：0)
您的colorPicker对象为null，并在以下行中生成NullPointerException。
colorPicker.addSaturationBar(saturationBar);
您需要检查自己的xml布局文件，ColorPicker未正确获取instantiate的原因。