问题
I am using Dialog in my app to allow user to make multiple selection, Here is my code:
btn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// Build an AlertDialog
AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);
// String array for alert dialog multi choice items
String[] colors = new String[]{
"Red",
"Green",
"Blue",
"Purple",
"Olive"
};
// Boolean array for initial selected items
final boolean[] checkedColors = new boolean[]{
false, // Red
false, // Green
false, // Blue
false, // Purple
false // Olive
};
// Convert the color array to list
final List<String> colorsList = Arrays.asList(colors);
// Set multiple choice items for alert dialog
builder.setMultiChoiceItems(colors, checkedColors, new DialogInterface.OnMultiChoiceClickListener() {
@Override
public void onClick(DialogInterface dialog, int which, boolean isChecked) {
// Update the current focused item's checked status
checkedColors[which] = isChecked;
// Get the current focused item
String currentItem = colorsList.get(which);
// Notify the current action
Toast.makeText(getApplicationContext(),
currentItem + " " + isChecked, Toast.LENGTH_SHORT).show();
}
});
// Specify the dialog is not cancelable
builder.setCancelable(false);
// Set a title for alert dialog
builder.setTitle("Your preferred colors?");
// Set the positive/yes button click listener
builder.setPositiveButton("OK", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
// Do something when click positive button
tv.setText("Your preferred colors..... \n");
for (int i = 0; i<checkedColors.length; i++){
boolean checked = checkedColors[i];
if (checked) {
tv.setText(tv.getText() + colorsList.get(i) + ", ");
}
}
}
});
// Set the negative/no button click listener
builder.setNegativeButton("No", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
// Do something when click the negative button
}
});
// Set the neutral/cancel button click listener
builder.setNeutralButton("Cancel", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
// Do something when click the neutral button
}
});
AlertDialog dialog = builder.create();
// Display the alert dialog on interface
dialog.show();
}
});
And I have two queries:
Like I have selected Red and Purple
(then in TextView getting output like this:
Red, Purple,)First of all I would like to remove comma (which getting with last value)
I already selected Red and Purple, when i again open dialog not getting red and purple as selected by default (How can i save the state)
enter code here, and as a result, when i am again selecting these (Red and Purple) two items, getting each item twice in a TextView
回答1:
Try updating your textview after the loop
And if your loop iteration reaches the length of the checkedcolors then donot append a comma.
public void onClick(DialogInterface dialog, int which) {
// Do something when click positive button
tv.setText("Your preferred colors..... \n");
for (int i = 0; i < checkedColors.length; i++) {
boolean checked = checkedColors[i];
String colors = "";
if (checked) {
colors = colors + colorsList.get(i) ;
if (i != checkedColors.length - 1) {
colors = colors + ", ";
}
}
}
tv.setText(tv.getText() + colors);
}
Yor textview will be updated only once, so you wont be getting each item twice in the TextView.
For saving the state you have to use SharedPreference.
For saving into preference use this
SharedPreferences preferences = mContext.getSharedPreferences("PREFERENCE_NAME", Context.MODE_PRIVATE);
SharedPreferences.Editor editor = preferences.edit();
editor.putBoolean("yourColor",isChecked);
editor.commit();
And to retrieve
boolean isChecked = preferences.getBoolean("yourColor");
回答2:
Please try this and improve structure of your code so that it can be managed efficiently.
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;
import java.util.ArrayList;
public class MainActivity extends AppCompatActivity {
private Button btn;
private TextView txtSelected;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
btn = (Button) findViewById(R.id.btn_dialog);
txtSelected = (TextView) findViewById(R.id.txt_selected);
final ArrayList<ColorVO> colorList = new ArrayList<ColorVO>();
// String array for alert dialog multi choice items
final String[] colors = new String[]{
"Red",
"Green",
"Blue",
"Purple",
"Olive"
};
// Boolean array for initial selected items
final boolean[] checkedColors = new boolean[]{
false, // Red
false, // Green
false, // Blue
false, // Purple
false // Olive
};
btn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);
// make a list to hold state of every color
for (int i = 0; i < colors.length; i++) {
ColorVO colorVO = new ColorVO();
colorVO.setName(colors[i]);
colorVO.setSelected(checkedColors[i]);
colorList.add(colorVO);
}
// Do something here to pass only arraylist on this both arrays ('colors' & 'checkedColors')
builder.setMultiChoiceItems(colors, checkedColors, new DialogInterface.OnMultiChoiceClickListener() {
@Override
public void onClick(DialogInterface dialog, int which, boolean isChecked) {
// set state to vo in list
colorList.get(which).setSelected(isChecked);
Toast.makeText(getApplicationContext(),
colorList.get(which).getName() + " " + isChecked, Toast.LENGTH_SHORT).show();
}
});
builder.setCancelable(false);
builder.setTitle("Your preferred colors?");
builder.setPositiveButton("OK", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
txtSelected.setText("Your preferred colors..... \n");
// save state of selected vos
ArrayList<ColorVO> selectedList = new ArrayList<>();
for (int i = 0; i < colorList.size(); i++) {
ColorVO colorVO = colorList.get(i);
colors[i] = colorVO.getName();
checkedColors[i] = colorVO.isSelected();
if (colorVO.isSelected()) {
selectedList.add(colorVO);
}
}
for (int i = 0; i < selectedList.size(); i++) {
// if element is last then not attach comma or attach it
if (i != selectedList.size() - 1)
txtSelected.setText(txtSelected.getText() + selectedList.get(i).getName() + " ,");
else
txtSelected.setText(txtSelected.getText() + selectedList.get(i).getName());
}
colorList.clear();
}
});
builder.setNegativeButton("No", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
// make sure to clear list that duplication dont formed here
colorList.clear();
}
});
builder.setNeutralButton("Cancel", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
// make sure to clear list that duplication dont formed here
colorList.clear();
}
});
AlertDialog dialog = builder.create();
dialog.show();
}
});
}
private class ColorVO {
private String name;
private boolean selected;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public boolean isSelected() {
return selected;
}
public void setSelected(boolean selected) {
this.selected = selected;
}
}
Solved all of your queries :
1. Like I have selected Red and Purple
=> Check for index of element, If it is last then do not attach comma.
2. I already selected Red and Purple, when i again open dialog not getting red and purple as selected by default (How can i save the state)
=> save state using vo in your default array.It will be saved until your activity is not destroyed.
3. when i am again selecting these (Red and Purple) two items, getting each item twice in a TextView
=> Clear list so that values do not get duplicated.
来源：https://stackoverflow.com/questions/32323605/how-do-i-control-on-multichoice-alertdialog