我有ArrayList ...
ArrayList<ColorSaver> tempList = new ArrayList<ColorSaver>();
我希望它能够在用户关闭应用或离开应用时，当用户重新打开应用时，ColorSaver中的所有ArrayList对象都会存在。我更喜欢使用SharedPreferences，但我不能这样做因为列表是自定义对象...
我环顾四周，发现我可以做一个序列化，但我尝试了这个并且失败了，所以如果有人可以引导我通过可序列化的交易，这将是伟大的。哦，我在哪里放置代码，例如我onCreate()或显示mainActivity的{{1}}中的activity
我的mainActivity类
ArrayList我的 public class MainActivity extends Activity {
ArrayList<ColorSaver> tempList = new ArrayList<ColorSaver>();
private static final String TAG = "Main Activity";
public static final String PREFS_NAME = "MyPrefsFile";
final Intent intent = new Intent();
@Override
public boolean onOptionsItemSelected(MenuItem item)
{
final NumberPicker rednp = (NumberPicker) findViewById(R.id.redNumberPicker1);
final NumberPicker bluenp = (NumberPicker) findViewById(R.id.blueNumberPicker);
final NumberPicker greennp = (NumberPicker) findViewById(R.id.greenNumberPicker);
switch(item.getItemId())
{
case R.id.save:
Log.i(TAG, "Save item clicked!");
Intent intent = new Intent(this, SaveActivity.class);
intent.putExtra("RedValue", rednp.getValue());
intent.putExtra("BlueValue", bluenp.getValue());
intent.putExtra("GreenValue", greennp.getValue());
intent.putExtra("temparray", tempList);
startActivity(intent);
return true;
case R.id.recall:
Log.i(TAG, "Recall item clicked!");
Intent intent2 = new Intent(this, RecallActivity.class);
intent2.putExtra("temparray", tempList);
startActivity(intent2);
return true;
default:
return super.onOptionsItemSelected(item);
}//End Switch
}
@SuppressWarnings("unchecked")
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//ArrayList<ColorSaver> tempList = new ArrayList<ColorSaver>();
Bundle extras = getIntent().getExtras();
final SurfaceView sView = (SurfaceView) findViewById(R.id.surfaceView1);
final NumberPicker np = (NumberPicker) findViewById(R.id.redNumberPicker1);
np.setMaxValue(255);
np.setMinValue(0);
final NumberPicker np2 = (NumberPicker) findViewById(R.id.greenNumberPicker);
np2.setMaxValue(255);
np2.setMinValue(0);
final NumberPicker np3 = (NumberPicker) findViewById(R.id.blueNumberPicker);
np3.setMaxValue(255);
np3.setMinValue(0);
if( extras != null )
{
np.setValue(extras.getInt("savedRValue"));
//np.setValue(intent.getIntExtra("savedRValue", 255));
np2.setValue(extras.getInt("savedGValue"));
//np2.setValue(intent.getIntExtra("savedGValue", 255));
np3.setValue(extras.getInt("savedBValue"));
//np3.setValue(intent.getIntExtra("savedBValue", 255));
tempList = (ArrayList<ColorSaver>) extras.getSerializable("array");
sView.setBackgroundColor(Color.argb(255, np.getValue(), np2.getValue(), np3.getValue()));
}
else
{
Log.i(TAG, "I just don't get it...WTF");
}
np.setOnValueChangedListener( new NumberPicker.
OnValueChangeListener() {
@Override
public void onValueChange(NumberPicker picker, int oldVal, int newVal)
{
int rednum, greennum, bluenum;
rednum = np.getValue();
greennum = np2.getValue();
bluenum = np3.getValue();
sView.setBackgroundColor(Color.argb(255, rednum, greennum, bluenum));
}
});
//GREEN NUMBERPICKER LISTENER
np2.setOnValueChangedListener( new NumberPicker.
OnValueChangeListener() {
@Override
public void onValueChange(NumberPicker picker, int oldVal, int newVal)
{
int rednum, greennum, bluenum;
rednum = np.getValue();
greennum = np2.getValue();
bluenum = np3.getValue();
sView.setBackgroundColor(Color.argb(255, rednum, greennum, bluenum));
}
});
np3.setOnValueChangedListener( new NumberPicker.
OnValueChangeListener() {
@Override
public void onValueChange(NumberPicker picker, int oldVal, int newVal)
{
int rednum, greennum, bluenum;
rednum = np.getValue();
greennum = np2.getValue();
bluenum = np3.getValue();
sView.setBackgroundColor(Color.argb(255, rednum, greennum, bluenum));
}
});
}//End onCreate()
@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;
}//END onCreateOptionsMenu()
}//END CLASS
，用户将其颜色组合保存到saveActivity ...
ArrayList我的 public class SaveActivity extends Activity implements Serializable {
private static final String TAG = "Save Activity";
public ArrayList<ColorSaver> savedColors = new ArrayList<ColorSaver>();
@SuppressWarnings("unchecked")
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_save);
// Show the Up button in the action bar.
setupActionBar();
Bundle extras = getIntent().getExtras();
final Intent intent1 = new Intent(this, MainActivity.class);
Button saveButton = (Button) findViewById(R.id.saveButton1);
final EditText nameField = (EditText) findViewById(R.id.colorNameField);
//final Intent intent = new Intent();
savedColors = (ArrayList<ColorSaver>) extras.getSerializable("temparray");
//Making sure the savedColors arrayList has something in it.
if( savedColors.isEmpty() )
{
ColorSaver temp = new ColorSaver("Rockies Purple", 180, 80, 255);
savedColors.add(temp);
}
saveButton.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
// Perform action on click
Bundle extras = getIntent().getExtras();
int redcolor, greencolor, bluecolor;
redcolor = extras.getInt("RedValue");
greencolor = extras.getInt("GreenValue");
bluecolor = extras.getInt("BlueValue");
String colorName = nameField.getText().toString();
//Build the new color and add it to the arrayList
ColorSaver saver = new ColorSaver(colorName, redcolor, greencolor, bluecolor);
savedColors.add(saver);
intent1.putExtra("array", savedColors);
Log.i(TAG, savedColors.get(savedColors.size()-1).getColorName());
startActivity(intent1);
}
});
}//END OnCreate()
/**
* Set up the {@link android.app.ActionBar}.
*/
private void setupActionBar() {
getActionBar().setDisplayHomeAsUpEnabled(true);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.save, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case android.R.id.home:
// This ID represents the Home or Up button. In the case of this
// activity, the Up button is shown. Use NavUtils to allow users
// to navigate up one level in the application structure. For
// more details, see the Navigation pattern on Android Design:
//
// http://developer.android.com/design/patterns/navigation.html#up-vs-back
//
NavUtils.navigateUpFromSameTask(this);
return true;
}
return super.onOptionsItemSelected(item);
}
}//END CLASS
用户回想起他们的颜色组合......
recallActivity我很满意任何帮助！
答案 0 :(得分：1)
了解Android的Parcelable实施。
所以，我只是猜测你的ColorSaver类，因为它没有发布，但是你可以通过以下方式实现它：
public class ColorSaver implements Parcelable {
private String mName;
private int mRed;
private int mGreen;
private int mBlue;
public int describeContents() {
return 0;
}
public void writeToParcel(Parcel out, int flags) {
out.writeString(mName);
out.writeInt(mRed);
out.writeInt(mGreen);
out.writeInt(mBlue);
}
public static final Parcelable.Creator<ColorSaver> CREATOR
= new Parcelable.Creator<ColorSaver>() {
public ColorSaver createFromParcel(Parcel in) {
return new ColorSaver(in);
}
public ColorSaver[] newArray(int size) {
return new ColorSaver[size];
}
};
private ColorSaver(Parcel in) {
mName = in.readString();
mRed = in.readInt();
mGreen = in.readInt();
mBlue = in.readInt();
}
}
public class MyActivity extends Activity {
private static final String COLOR_SAVER_LIST = "com.example.android.ColorSaverList";
private List<ColorSaver> colorSaverList;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (savedInstanceState != null && savedInstanceState.containsKey(COLOR_SAVER_LIST)) {
colorSaverList = new ArrayList<ColorSaver>();
colorSaverList = savedInstanceState.getParcelableArrayList(COLOR_SAVER_LIST);
}
}
@Override
public void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
outState.putParcelableArrayList(COLOR_SAVER_LIST, colorSaverList);
}
}