我写了一个Android应用程序，它只显示一个列表视图。 一切都很好，除了一个。 我在平板电脑上安装了我的应用程序，当我运行应用程序时，就会出现问题。 ==取代。那是 。 。 。 当我按下电源按钮关闭屏幕并再次按电源按钮打开屏幕时，整个列表视图数据消失。
我认为这是活动生命周期的一些问题，但我无法解决这个问题。
请帮帮我..
这是我的代码......
package com.jo.fivemancard;
import android.content.Context;
import android.os.Handler;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;
import java.util.ArrayList;
public class MainActivity extends AppCompatActivity implements View.OnClickListener {
public ScoreListAdapter scoreListAdapter;
class RoundScore {
public int score1 = 0;
public int score2 = 0;
public int score3 = 0;
public int score4 = 0;
public int score5 = 0;
public RoundScore(){
score1 = score2 = score3 = score4 = score5 = 0;
}
}
class ScoreListAdapter extends BaseAdapter{
public Context context;
class ViewHolder{
TextView textViewScore1;
TextView textViewScore2;
TextView textViewScore3;
TextView textViewScore4;
TextView textViewScore5;
}
public ArrayList<RoundScore> scoreList;
public ScoreListAdapter(Context cont){
context = cont;
scoreList = new ArrayList<RoundScore>();
}
public void appendData(RoundScore rc){
scoreList.add(rc);
notifyDataSetChanged();
}
@Override
public int getCount() {
return scoreList.size();
}
@Override
public Object getItem(int position) {
return scoreList.get(position);
}
@Override
public long getItemId(int position) {
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder vh;
if(convertView == null) {
LayoutInflater inflater = (LayoutInflater) context
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View rowView = inflater.inflate(R.layout.listviewitem_score, parent, false);
vh = new ViewHolder();
vh.textViewScore1 = (TextView)rowView.findViewById(R.id.textViewScore1);
vh.textViewScore2 = (TextView)rowView.findViewById(R.id.textViewScore2);
vh.textViewScore3 = (TextView)rowView.findViewById(R.id.textViewScore3);
vh.textViewScore4 = (TextView)rowView.findViewById(R.id.textViewScore4);
vh.textViewScore5 = (TextView)rowView.findViewById(R.id.textViewScore5);
convertView = rowView;
}else {
vh = (ViewHolder) convertView.getTag();
}
RoundScore rc = scoreList.get(position);
vh.textViewScore1.setText("" + rc.score1);
vh.textViewScore2.setText("" + rc.score2);
vh.textViewScore3.setText("" + rc.score3);
vh.textViewScore4.setText("" + rc.score4);
vh.textViewScore5.setText("" + rc.score5);
convertView.setTag(vh);
return convertView;
}
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
findViewById(R.id.buttonNextRound).setOnClickListener(this);
findViewById(R.id.floatActionButtonCalculate).setOnClickListener(this);
scoreListAdapter = new ScoreListAdapter(this);
((ListView)findViewById(R.id.listViewScore)).setAdapter(scoreListAdapter);
((TextView)findViewById(R.id.textViewPlayer1)).setText(GlobalConstant.playername1);
((TextView)findViewById(R.id.textViewPlayer2)).setText(GlobalConstant.playername2);
((TextView)findViewById(R.id.textViewPlayer3)).setText(GlobalConstant.playername3);
((TextView)findViewById(R.id.textViewPlayer4)).setText(GlobalConstant.playername4);
((TextView)findViewById(R.id.textViewPlayer5)).setText(GlobalConstant.playername5);
}
public int getScore(String score){
if(score.trim().equals("")){
return 0;
}
if(score.length() == 0){
return 0;
}
boolean isNumber;
if(score.charAt(0) == '-'){
isNumber = android.text.TextUtils.isDigitsOnly(score.substring(1));
}else{
isNumber = android.text.TextUtils.isDigitsOnly(score);
}
if(isNumber) {
return Integer.parseInt(score.trim());
}
return 0;
}
@Override
public void onClick(View v) {
if(v.getId() == R.id.buttonNextRound){
String score1 = ((EditText)findViewById(R.id.editTextNewScorePlayer1)).getText().toString();
String score2 = ((EditText)findViewById(R.id.editTextNewScorePlayer2)).getText().toString();
String score3 = ((EditText)findViewById(R.id.editTextNewScorePlayer3)).getText().toString();
String score4 = ((EditText)findViewById(R.id.editTextNewScorePlayer4)).getText().toString();
String score5 = ((EditText)findViewById(R.id.editTextNewScorePlayer5)).getText().toString();
if(score1.trim().equals("")){
score1 = "0";
}
RoundScore rc = new RoundScore();
rc.score1 = getScore(score1);
rc.score2 = getScore(score2);
rc.score3 = getScore(score3);
rc.score4 = getScore(score4);
rc.score5 = getScore(score5);
if(rc.score1 == 0 && rc.score2 == 0 && rc.score3 == 0 && rc.score4 == 0 && rc.score5 == 0){
Toast.makeText(this, "Bad Input...", Toast.LENGTH_SHORT).show();
return;
}
scoreListAdapter.appendData(rc);
((ListView)findViewById(R.id.listViewScore)).setSelection(scoreListAdapter.getCount() - 1);
Toast.makeText(this, "Next Round...", Toast.LENGTH_SHORT).show();
((EditText)findViewById(R.id.editTextNewScorePlayer1)).setText("");
((EditText)findViewById(R.id.editTextNewScorePlayer2)).setText("");
((EditText)findViewById(R.id.editTextNewScorePlayer3)).setText("");
((EditText)findViewById(R.id.editTextNewScorePlayer4)).setText("");
((EditText)findViewById(R.id.editTextNewScorePlayer5)).setText("");
}
if(v.getId() == R.id.floatActionButtonCalculate){
RoundScore rs = new RoundScore();
int i;
for(i=0;i<scoreListAdapter.scoreList.size();i++){
rs.score1 += scoreListAdapter.scoreList.get(i).score1;
rs.score2 += scoreListAdapter.scoreList.get(i).score2;
rs.score3 += scoreListAdapter.scoreList.get(i).score3;
rs.score4 += scoreListAdapter.scoreList.get(i).score4;
rs.score5 += scoreListAdapter.scoreList.get(i).score5;
}
if(findViewById(R.id.buttonNextRound).isEnabled()){
String str1 = ((EditText)findViewById(R.id.editTextNewScorePlayer1)).getText().toString().trim();
String str2 = ((EditText)findViewById(R.id.editTextNewScorePlayer2)).getText().toString().trim();
String str3 = ((EditText)findViewById(R.id.editTextNewScorePlayer3)).getText().toString().trim();
String str4 = ((EditText)findViewById(R.id.editTextNewScorePlayer4)).getText().toString().trim();
String str5 = ((EditText)findViewById(R.id.editTextNewScorePlayer5)).getText().toString().trim();
if(!str1.equals("") || !str2.equals("") || !str3.equals("") || !str4.equals("") || !str5.equals("")){
Toast.makeText(this,"It seems you wanna add score info.",Toast.LENGTH_SHORT);
return;
}
findViewById(R.id.buttonNextRound).setEnabled(false);
((EditText)findViewById(R.id.editTextNewScorePlayer1)).setText("" + rs.score1);
((EditText)findViewById(R.id.editTextNewScorePlayer2)).setText("" + rs.score2);
((EditText)findViewById(R.id.editTextNewScorePlayer3)).setText("" + rs.score3);
((EditText)findViewById(R.id.editTextNewScorePlayer4)).setText("" + rs.score4);
((EditText)findViewById(R.id.editTextNewScorePlayer5)).setText("" + rs.score5);
((EditText)findViewById(R.id.editTextNewScorePlayer1)).setEnabled(false);
((EditText)findViewById(R.id.editTextNewScorePlayer2)).setEnabled(false);
((EditText)findViewById(R.id.editTextNewScorePlayer3)).setEnabled(false);
((EditText)findViewById(R.id.editTextNewScorePlayer4)).setEnabled(false);
((EditText)findViewById(R.id.editTextNewScorePlayer5)).setEnabled(false);
}else{
findViewById(R.id.buttonNextRound).setEnabled(true);
((EditText)findViewById(R.id.editTextNewScorePlayer1)).setText("");
((EditText)findViewById(R.id.editTextNewScorePlayer2)).setText("");
((EditText)findViewById(R.id.editTextNewScorePlayer3)).setText("");
((EditText)findViewById(R.id.editTextNewScorePlayer4)).setText("");
((EditText)findViewById(R.id.editTextNewScorePlayer5)).setText("");
((EditText)findViewById(R.id.editTextNewScorePlayer1)).setEnabled(true);
((EditText)findViewById(R.id.editTextNewScorePlayer2)).setEnabled(true);
((EditText)findViewById(R.id.editTextNewScorePlayer3)).setEnabled(true);
((EditText)findViewById(R.id.editTextNewScorePlayer4)).setEnabled(true);
((EditText)findViewById(R.id.editTextNewScorePlayer5)).setEnabled(true);
}
}
}
private Boolean exit = false;
@Override
public void onBackPressed() {
if (exit) {
finish(); // finish activity
} else {
Toast.makeText(this, "Press Back again to Exit.",
Toast.LENGTH_SHORT).show();
exit = true;
new Handler().postDelayed(new Runnable() {
@Override
public void run() {
exit = false;
}
}, 1 * 1000);
}
}
}