Question

我想在应用的第一次启动时弹出一个免责声明。如果用户拒绝，应用程序将关闭。如果用户再次打开应用程序，则应再次弹出免责声明，直到用户接受为止。一旦被接受，它应该隐藏，不再弹出。

我的问题：如果我接受了免责声明，它会关闭，一切都很好。但是当我启动应用程序时，它会再次弹出。

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);


    final SharedPreferences pref = getSharedPreferences("Preferences", MODE_PRIVATE);

    String lver = pref.getString("Version", "");
    String ver = this.getString(R.string.version);
    if(ver != lver)
    {
        AlertDialog.Builder builder = new AlertDialog.Builder(this);
        builder.setTitle("Disclaimer")
            .setMessage(this.getString(R.string.disclaimer))
            .setCancelable(false)
            .setIcon(R.drawable.caution)
            .setPositiveButton("Accept", new DialogInterface.OnClickListener() {
                SharedPreferences.Editor edit = pref.edit();
                public void onClick (DialogInterface dialog, int id) { 

                    boolean accepted = true;
                    dialog.cancel();
                    if(accepted == true)
                    {
                    edit.putString("Version", this.getString(R.string.version));
                    edit.commit();}
                }
                private String getString(int version) {
                    // I had to create this method, cause i got an error the line above this.getstring(R.string.version)
                    return null;
                }
            })
            .setNegativeButton("Decline", new DialogInterface.OnClickListener() {
                public void onClick(DialogInterface dialog, int id) {
                    MainActivity.this.finish();
                }
            });
        AlertDialog disc = builder.create();
        disc.show();
 } }

我找到了quite similar question，但我无法解决我的问题。

我会对答案感到高兴，如果可能的话，我会在代码中给出一个很好的解释。因为我想了解更多/为什么它解决了我的问题而且不想复制＆amp;插入代码并对它的工作感到高兴。

Answer 1

您的问题是if条件ver != lver，因为您应该使用equals检查字符串是否相等。

if(ver.equals(lver))

因为这个问题已经讨论了很多次，所以link应该很好地解释它。

此外更改此部分（我在代码中注释）

    // this doesn't belong here. get it in onClick of the positive Button
    final SharedPreferences pref = getSharedPreferences("Preferences", MODE_PRIVATE);
    builder.setTitle("Disclaimer")
        .setMessage(this.getString(R.string.disclaimer))
        .setCancelable(false)
        .setIcon(R.drawable.caution)
        .setPositiveButton("Accept", new DialogInterface.OnClickListener() {
            SharedPreferences.Editor edit = pref.edit(); // the same as with the pef object
            public void onClick (DialogInterface dialog, int id) { 

                boolean accepted = true; // no need for this because the if clause will always be true
                dialog.cancel(); // cancel the dialog IF the job here is done
                if(accepted == true)
                {
                edit.putString("Version", this.getString(R.string.version)); // delete the this pointer
                edit.commit();}
            }
            // no need for this method
            private String getString(int version) {
                // I had to create this method, cause i got an error the line above this.getstring(R.string.version)
                return null;
            }
        });
        .setNegativeButton("Decline", new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int id) {
                MainActivity.this.finish();
            }
        });

到这个

    builder.setTitle("Disclaimer")
        .setMessage(this.getString(R.string.disclaimer))
        .setCancelable(false)
        .setIcon(R.drawable.caution)
        .setPositiveButton("Accept", new DialogInterface.OnClickListener() {

            public void onClick (DialogInterface dialog, int id) { 
                SharedPreferences pref = getSharedPreferences("Preferences", MODE_PRIVATE);
                SharedPreferences.Editor edit = pref.edit();
                edit.putString("Version", getString(R.string.version));
                edit.commit();
                dialog.cancel();
            }

        });
        .setNegativeButton("Decline", new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int id) {
                MainActivity.this.finish();
            }
        });

现在应该没问题

Answer 2

看起来您正在将两个String与!=运算符进行比较。在Java中比较字符串的正确方法是使用.equals(String string)函数。

您的比较应该如下所示：

if(!ver.equals(lver)){
    ...
}

Answer 3

**谢谢大家的答案...... 但根据我的关注，免责声明对话框应该是这样的 enter image description here

 i have customise the Dialog and used the same logic of SharedPrefence to save the users choice.
    The source code are ---
   ****MainActivity.java ***** 
    public class MainActivity extends Activity {
        SharedPreferences   prefs ;

        boolean isShowAgain=true;
        boolean accepted=false;
        CheckBox dialogcb;
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
            prefs = getSharedPreferences("detail", MODE_PRIVATE);
            boolean isshowagain =prefs.getBoolean("show_again", true);
             if(isshowagain)
                showdialog();
        }
        private void showdialog() {
            final Dialog dialog = new Dialog(this);
            dialog.setContentView(R.layout.custom_dialog);
            dialog.setTitle("Disclaimer...");
            Button dialogButton = (Button) dialog.findViewById(R.id.button1);
           dialogcb= (CheckBox) dialog.findViewById(R.id.checkBox1);
            dialogButton.setOnClickListener(new OnClickListener() {
                @Override
                public void onClick(View v) {
                        accepted = dialogcb.isChecked();
                        SharedPreferences.Editor edit=prefs.edit();
                        edit.putBoolean("show_again",!accepted);
                        edit.commit();
                       dialog.dismiss();
                }
            });
            dialog.show();
        }
    }*


    and the custom_dialog.xml is---
    <?xml version="1.0" encoding="utf-8"?>
    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:orientation="vertical" >
        <TextView
            android:id="@+id/textView1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
             android:layout_marginBottom="10dip"
            android:layout_marginLeft="20dip"
            android:layout_marginRight="20dip"
            android:layout_marginTop="10dip"
            android:text="This is alert dialog will run  every time when App will launch .
            if you want to close for always just check on check box and then press agree button" />
        <CheckBox
            android:id="@+id/checkBox1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Do not show it Again." />
        <Button
            android:id="@+id/button1"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginBottom="5dip"
            android:layout_marginLeft="5dip"
            android:layout_marginRight="5dip"
            android:layout_marginTop="5dip"
            android:text="Agree" />
    </LinearLayout>*

alertDialog免责声明显示每次运行

3 个答案: