我不确定如何正确构建这个地块；当我null尝试从我的MainActivity.
发送intent：
public void onClick(View v) {
Intent myIntent = new Intent(listaddactivity.this,
MainActivity.class);
myIntent.putExtra(
"custom_object",
new listControlObject(namefield.getText().toString(),
iterator, temperatureFrag.getCurrentTempType(), Integer
.valueOf(powerPercent.getText()
.toString()), Integer
.valueOf(frequencyField.getText()
.toString()),
temperatureFrag.temperaturenumberpicker
.getValue(), cycleFrag.startTimeField
.getCurrentHour(),
cycleFrag.startTimeField.getCurrentMinute(),
cycleFrag.cycleDatePicker.getDayOfMonth(),
cycleFrag.cycleDatePicker.getMonth(), Integer
.valueOf(cycleFrag.numberOfCyclesField
.getText().toString()))); // Optional
// parameters
startActivity(myIntent);
Log.d("LISTACTIVITY", "Intent successfully passed!");
iterator++;
}
});
}
接收activity：
public class MainActivity extends FragmentActivity implements
ActionBar.TabListener {
String TAG;
HomeFragment homeFragment;
cycleviewfragment cyclefragment;
SectionsPagerAdapter mSectionsPagerAdapter;
/**
* The {@linkCustomViewPager} that will host the section contents.
*/
CustomViewPager mViewPager;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Set up the action bar.
final ActionBar actionBar = getActionBar();
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
homeFragment = new HomeFragment();
cyclefragment = new cycleviewfragment();
// Create the adapter that will return a fragment for each of the three
// primary sections of the app.
mSectionsPagerAdapter = new SectionsPagerAdapter(
getSupportFragmentManager());
// Set up theCustomViewPager with the sections adapter.
mViewPager = (CustomViewPager) findViewById(R.id.pager);
mViewPager.setAdapter(mSectionsPagerAdapter);
mViewPager.setPagingEnabled(false);
// When swiping between different sections, select the corresponding
// tab. We can also use ActionBar.Tab#select() to do this if we have
// a reference to the Tab.
mViewPager
.setOnPageChangeListener(new CustomViewPager.SimpleOnPageChangeListener() {
@Override
public void onPageSelected(int position) {
actionBar.setSelectedNavigationItem(position);
}
});
// For each of the sections in the app, add a tab to the action bar.
for (int i = 0; i < mSectionsPagerAdapter.getCount(); i++) {
// Create a tab with text corresponding to the page title defined by
// the adapter. Also specify this Activity object, which implements
// the TabListener interface, as the callback (listener) for when
// this tab is selected.
actionBar.addTab(actionBar.newTab()
.setText(mSectionsPagerAdapter.getPageTitle(i))
.setTabListener(this));
}
processNewIntent(getIntent());
}
@Override
protected void onNewIntent(Intent intent) {
super.onNewIntent(intent);
processNewIntent(intent);
}
private void processNewIntent(Intent intent) {
Log.v("TEST", "METHOD CALLED TEST");
if (intent.hasExtra("custom_object")) {
cyclefragment.a1.add((listControlObject) intent.getParcelableExtra("custom_object"));
cyclefragment.adapter.notifyDataSetChanged();
}
}
我发送包裹时是否错误地执行了包裹intent？有没有理由我processNewIntent给我一个NullPointerException？
我猜有一种特定的方法可以构建一个包裹并将其传递给我没有正确实现的意图，但我找不到任何好的资源。
Logcat：
03-24 01:13:30.846: E/Trace(7974): error opening trace file: No such file or directory (2)
03-24 01:13:44.374: E/AndroidRuntime(7974): FATAL EXCEPTION: main
03-24 01:13:44.374: E/AndroidRuntime(7974): java.lang.NullPointerException
03-24 01:13:44.374: E/AndroidRuntime(7974): at com.nanospark.upcdemo.listaddactivity$1.onClick(listaddactivity.java:72)
03-24 01:13:44.374: E/AndroidRuntime(7974): at android.view.View.performClick(View.java:4091)
03-24 01:13:44.374: E/AndroidRuntime(7974): at android.view.View$PerformClick.run(View.java:17072)
03-24 01:13:44.374: E/AndroidRuntime(7974): at android.os.Handler.handleCallback(Handler.java:615)
03-24 01:13:44.374: E/AndroidRuntime(7974): at android.os.Handler.dispatchMessage(Handler.java:92)
03-24 01:13:44.374: E/AndroidRuntime(7974): at android.os.Looper.loop(Looper.java:153)
03-24 01:13:44.374: E/AndroidRuntime(7974): at android.app.ActivityThread.main(ActivityThread.java:4987)
03-24 01:13:44.374: E/AndroidRuntime(7974): at java.lang.reflect.Method.invokeNative(Native Method)
03-24 01:13:44.374: E/AndroidRuntime(7974): at java.lang.reflect.Method.invoke(Method.java:511)
03-24 01:13:44.374: E/AndroidRuntime(7974): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:821)
03-24 01:13:44.374: E/AndroidRuntime(7974): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:584)
03-24 01:13:44.374: E/AndroidRuntime(7974): at dalvik.system.NativeStart.main(Native Method)
多谢你们。
编辑：
listaddactivity.java 的第 72 行：
myIntent.putExtra(
"custom_object",
new listControlObject(namefield.getText().toString(),
iterator, temperatureFrag.getCurrentTempType(), Integer
.valueOf(powerPercent.getText()
.toString()), Integer
.valueOf(frequencyField.getText()
.toString()),
temperatureFrag.temperaturenumberpicker
.getValue(), cycleFrag.startTimeField
.getCurrentHour(),
cycleFrag.startTimeField.getCurrentMinute(),
cycleFrag.cycleDatePicker.getDayOfMonth(),
cycleFrag.cycleDatePicker.getMonth(), Integer
.valueOf(cycleFrag.numberOfCyclesField
.getText().toString())));
以上只是构造一个新对象并将其添加到具有键“自定义对象”的意图中。
以下是可打包对象的代码：
package com.nanospark.upcdemo;
import android.os.Parcel;
import android.os.Parcelable;
public class listControlObject implements Parcelable {
private String name;
private int id;
private int tempType;// 0 for fahrenheit, 1 for celsius.
private int powerPercent;
private int freq;
private int temp;
private int cycleDateDay;
private int cycleDateMonth;
private int numberOfCycles;
private int cycleTimeHour;
private int cycleTimeMinute;
public listControlObject(String name, int id, int tempType,
int powerPercent, int freq, int temp, int cycleTimeHour,
int cycleTimeMinute, int cycleDateDay, int cycleDateMonth,
int numberOfCycles) {
this.id = id;
this.name = name;
this.cycleDateDay = cycleDateDay;
this.cycleDateMonth = cycleDateMonth;
this.cycleTimeHour = cycleTimeHour;
this.cycleTimeMinute = cycleTimeMinute;
this.freq = freq;
this.numberOfCycles = numberOfCycles;
this.powerPercent = powerPercent;
this.temp = temp;
this.tempType = tempType;
}
private listControlObject(Parcel in){
this.id = in.readInt();
this.name = in.readString();
this.cycleDateDay = in.readInt();
this.cycleDateMonth = in.readInt();
this.cycleTimeHour = in.readInt();
this.cycleTimeMinute = in.readInt();
this.freq = in.readInt();
this.numberOfCycles = in.readInt();
this.powerPercent = in.readInt();
this.temp = in.readInt();
this.tempType = in.readInt();
}
public int getCycleDateDay() {
return cycleDateDay;
}
public void setCycleDateDay(int cycleDateDay) {
this.cycleDateDay = cycleDateDay;
}
public int getCycleDateMonth() {
return cycleDateMonth;
}
public void setCycleDateMonth(int cycleDateMonth) {
this.cycleDateMonth = cycleDateMonth;
}
public int getCycleTimeHour() {
return cycleTimeHour;
}
public void setCycleTimeHour(int cycleTimeHour) {
this.cycleTimeHour = cycleTimeHour;
}
public int getCycleTimeMinute() {
return cycleTimeMinute;
}
public void setCycleTimeMinute(int cycleTimeMinute) {
this.cycleTimeMinute = cycleTimeMinute;
}
public int getNumberOfCycles() {
return numberOfCycles;
}
public void setNumberOfCycles(int numberOfCycles) {
this.numberOfCycles = numberOfCycles;
}
public int getTempType() {
return tempType;
}
public void setTempType(int tempType) {
this.tempType = tempType;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getPowerPercent() {
return powerPercent;
}
public void setPowerPercent(int powerPercent) {
this.powerPercent = powerPercent;
}
public int getFreq() {
return freq;
}
public void setFreq(int freq) {
this.freq = freq;
}
public int getTemp() {
return temp;
}
public void setTemp(int temp) {
this.temp = temp;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
@Override
public String toString() {
return this.name;
}
@Override
public int describeContents() {
// TODO Auto-generated method stub
return 0;
}
@Override
public void writeToParcel(Parcel parcel, int flags) {
parcel.writeInt(id);
parcel.writeString(name);
parcel.writeInt(cycleDateDay);
parcel.writeInt(cycleDateMonth);
parcel.writeInt(cycleTimeHour);
parcel.writeInt(cycleTimeMinute);
parcel.writeInt(freq);
parcel.writeInt(numberOfCycles);
parcel.writeInt(powerPercent);
parcel.writeInt(temp);
parcel.writeInt(tempType);
}
public static Creator<listControlObject> CREATOR = new Creator<listControlObject>() {
public listControlObject createFromParcel(Parcel parcel) {
return new listControlObject(parcel);
}
public listControlObject[] newArray(int size) {
return new listControlObject[size];
}
};
}
编辑：
我发现了我的错误的根源：
当我需要传递一个listControlObject 时，我在这里传递一个包裹。
cyclefragment.a1.add(intent.getParcelableExtra("custom_object"));
cyclefragment.adapter.notifyDataSetChanged();
如何将该 intent.getParcelableExtra("custom_object") 转换回 listControlObject？
[更新]
新的 Logcat 错误：
03-24 02:29:46.177: E/AndroidRuntime(9685): FATAL EXCEPTION: main
03-24 02:29:46.177: E/AndroidRuntime(9685): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.nanospark.upcdemo/com.nanospark.upcdemo.MainActivity}: java.lang.NullPointerException
03-24 02:29:46.177: E/AndroidRuntime(9685): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2184)
03-24 02:29:46.177: E/AndroidRuntime(9685): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2211)
03-24 02:29:46.177: E/AndroidRuntime(9685): at android.app.ActivityThread.access$600(ActivityThread.java:149)
03-24 02:29:46.177: E/AndroidRuntime(9685): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1300)
03-24 02:29:46.177: E/AndroidRuntime(9685): at android.os.Handler.dispatchMessage(Handler.java:99)
03-24 02:29:46.177: E/AndroidRuntime(9685): at android.os.Looper.loop(Looper.java:153)
03-24 02:29:46.177: E/AndroidRuntime(9685): at android.app.ActivityThread.main(ActivityThread.java:4987)
03-24 02:29:46.177: E/AndroidRuntime(9685): at java.lang.reflect.Method.invokeNative(Native Method)
03-24 02:29:46.177: E/AndroidRuntime(9685): at java.lang.reflect.Method.invoke(Method.java:511)
03-24 02:29:46.177: E/AndroidRuntime(9685): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:821)
03-24 02:29:46.177: E/AndroidRuntime(9685): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:584)
03-24 02:29:46.177: E/AndroidRuntime(9685): at dalvik.system.NativeStart.main(Native Method)
03-24 02:29:46.177: E/AndroidRuntime(9685): Caused by: java.lang.NullPointerException
03-24 02:29:46.177: E/AndroidRuntime(9685): at com.nanospark.upcdemo.MainActivity.processNewIntent(MainActivity.java:88)
03-24 02:29:46.177: E/AndroidRuntime(9685): at com.nanospark.upcdemo.MainActivity.onCreate(MainActivity.java:70)
03-24 02:29:46.177: E/AndroidRuntime(9685): at android.app.Activity.performCreate(Activity.java:5020)
03-24 02:29:46.177: E/AndroidRuntime(9685): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
03-24 02:29:46.177: E/AndroidRuntime(9685): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2148)
03-24 02:29:46.177: E/AndroidRuntime(9685): ... 11 more
相关代码：
@Override
protected void onNewIntent(Intent intent) {
super.onNewIntent(intent);
processNewIntent(intent);
}
private void processNewIntent(Intent intent) {
Log.v("TEST", "METHOD CALLED TEST");
if (intent.hasExtra("custom_object")) {
if (intent.getParcelableExtra("custom_object")
.equals(null)) {
Log.v("Testing null", "Object is null");
} else {
Log.v("Testing null", "Object is not null");
cyclefragment.a1.add((listControlObject) intent.getParcelableExtra("custom_object"));
cyclefragment.adapter.notifyDataSetChanged();
}
}
}
logcat 错误指的是这一行：
cyclefragment.a1.add((listControlObject) intent.getParcelableExtra("custom_object"));
我做了
private listControlObject(Parcel in){
public listControlObject(Parcel in){
根据评论的要求。仍然收到错误。