java - 即使在实现 onSaveInstanceState() 和 onRestoreInstanceState() 方法后也无法保存我的 Activity 状态

Question

我正在设置一个要在其中添加卡片布局的应用程序。单击添加按钮后，将添加一张包含用户名和详细信息的卡片。单击卡片时，将打开一个新 Activity 。一切正常，除了当我关闭 Activity 时，所有添加的卡片都消失了，应用程序开始完全空白。 此外，在添加卡片后更改应用程序方向时，应用程序崩溃会导致泄漏窗口异常。 Kinsly帮我解决一下

我已经覆盖了代码末尾可见的 onSaveInstanceState() 和 onRestoreInstanceState() 方法。

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    setContentView(R.layout.activity_layout);

    mcontext=this;

    buttonScan = findViewById(R.id.fab);

    adapter = new ArrayAdapter<>(this, android.R.layout.simple_list_item_1, arrayList);
    dialog1 = new Dialog(Activity.this);
    context = getApplicationContext();

   /* SharedPreferences sharedPref = getPreferences(Context.MODE_PRIVATE);
    boolean shouldDisplayCard = sharedPref.getBoolean("should_display_card", false);

    if(shouldDisplayCard)
        cardview();*/

    buttonScan.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            addhome();
            /* scanWifi();
            dialog1.setContentView(R.layout.activity_scan);
            dialog1.setTitle("Scanning");
            listView = dialog1.findViewById(R.id.wifiList);
            listView.setAdapter(adapter);
            dialog1.show();*/
        }
    });

    homeLayout = findViewById(R.id.homelayout);

    LayoutParams lparams = new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
    tv = new TextView(this);
    tv.setLayoutParams(lparams);
    tv.setText("Currently no device is added, Tap '+' to add a new device.");
    tv.setTextSize(21);
    tv.setGravity(Gravity.CENTER);
    tv.setPadding(70, 470, 70, 50);
    homeLayout.addView(tv);

}

public void addhome() {
    dialog2 = new Dialog(Activity.this);
    dialog2.setContentView(R.layout.add_home);
    v = View.inflate(this, R.layout.add_home, null);
    dialog2.setContentView(v);
    dialog2.show();

    editText1 = v.findViewById(R.id.editText);
    passtext1 = v.findViewById(R.id.passText1);
    passtext2 = v.findViewById(R.id.passText2);

    homebut = v.findViewById(R.id.homeBut);

    homebut.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            if (editText1.getText().toString().trim().length() <= 0)
                Toast.makeText(getApplicationContext(), "Please input Home name", Toast.LENGTH_SHORT).show();
            else if (passtext1.getText().toString().trim().length() <= 0 || passtext2.getText().toString().trim().length() <= 0)
                Toast.makeText(getApplicationContext(), "Please enter Password", Toast.LENGTH_SHORT).show();
            else if (!passtext1.getText().toString().trim().equals(passtext2.getText().toString().trim()))
                Toast.makeText(getApplicationContext(), "Passwords do not match", Toast.LENGTH_SHORT).show();
            else {
                pass1 = passtext1.getText().toString().trim();
                pass2 = passtext2.getText().toString().trim();
                cardview();
                /*SharedPreferences sharedPref = mcontext.getPreferences(Context.MODE_PRIVATE);
                SharedPreferences.Editor editor = sharedPref.edit();
                editor.putBoolean("should_display_card", true);
                editor.apply();*/
                dialog2.hide();
                homeLayout.removeView(tv);
            }
        }
    });
}

public void cardview() {

    cardview = new CardView(context);
    layoutparams1 = new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT);
    layoutparams1.setMargins(18, 30, 18, 0);
    cardview.setLayoutParams(layoutparams1);
    cardview.setCardBackgroundColor(Color.WHITE);
    cardview.setMinimumHeight(400);
    cardview.setRadius(30);

    textview1 = new TextView(context);
    //textview1.setLayoutParams(layoutparams1);
    textview1.setText(editText1.getText().toString().trim());
    textview1.setTextSize(TypedValue.COMPLEX_UNIT_DIP, 28);
    textview1.setTypeface(null, Typeface.BOLD);
    textview1.setTextColor(Color.GRAY);
    textview1.setPadding(30, 35, 25, 65);
    textview1.setGravity(Gravity.TOP);
    textview1.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            Intent intent = new Intent(Activity.this, MainActivity.class);
            Activity.this.startActivity(intent);
        }
    });

    textview2 = new TextView(context);
   // textview2.setLayoutParams(layoutparams1);
    textview2.setText("Connection: ");
    textview2.setTextSize(TypedValue.COMPLEX_UNIT_DIP, 20);
    textview2.setTextColor(Color.GRAY);
    textview2.setPadding(30, 165, 25, 45);
    textview2.setGravity(Gravity.TOP);

    textview3 = new TextView(context);
   // textview3.setLayoutParams(layoutparams1);
    textview3.setText("Security: ");
    textview3.setTextSize(TypedValue.COMPLEX_UNIT_DIP, 20);
    textview3.setTextColor(Color.GRAY);
    textview3.setPadding(30, 255, 25, 45);
    textview3.setGravity(Gravity.TOP);

    textview4 = new TextView(context);
    //textview4.setLayoutParams(layoutparams1);
    textview4.setText("Active");
    textview4.setTextColor(Color.GREEN);
    textview4.setTextSize(TypedValue.COMPLEX_UNIT_DIP, 20);
    textview4.setPadding(450,  165, 25, 45);
    textview4.setGravity(Gravity.TOP);

    textview5 = new TextView(context);
    textview5.setLayoutParams(layoutparams1);
    textview5.setText("Inactive");
    textview5.setTextColor(Color.RED);
    textview5.setTextSize(TypedValue.COMPLEX_UNIT_DIP, 20);
    textview5.setPadding(450, 215, 25, 45);
    textview5.setGravity(Gravity.TOP);

    cardview.addView(textview1);
    cardview.addView(textview2);
    cardview.addView(textview3);
    cardview.addView(textview4);
    cardview.addView(textview5);

    homeLayout.addView(cardview);
}

@Override
public void onSaveInstanceState(Bundle outState) {
    super.onSaveInstanceState(outState);
    Log.i(TAG, "onSaveInstanceState");
    final EditText textBox = v.findViewById(R.id.editText);
    CharSequence userText = textBox.getText();
    outState.putCharSequence("savedText", userText);
}

@Override
public void onRestoreInstanceState(Bundle savedInstanceState) {
    super.onRestoreInstanceState(savedInstanceState);
    Log.i(TAG, "onRestoreInstanceState");
    final EditText textBox = v.findViewById(R.id.editText);
    CharSequence userText = savedInstanceState.getCharSequence("savedText");
    textBox.setText(userText);
}

Answer 1

您必须将它们存储在本地数据库中。 尝试 Room