Java 如何将数据从活动传递到DialogFragment_Java_Android_Android Activity_Nullpointerexception_Android Dialogfragment

Java 如何将数据从活动传递到DialogFragment

java android

Java 如何将数据从活动传递到DialogFragment,java,android,android-activity,nullpointerexception,android-dialogfragment,Java,Android,Android Activity,Nullpointerexception,Android Dialogfragment,我知道有一些关于如何将数据从活动传递到对话框（即捆绑或意图）的示例。然而，我所尝试的一切都不起作用。我不断收到NPE和“找不到显式活动类”错误。即使我用对话框构建一个超基本活动，它也不起作用。我必须在代码中添加什么才能使其工作主要活动： public class MainActivity extends AppCompatActivity { Button button; String textIWantToSee; @Override protected void onC

我知道有一些关于如何将数据从活动传递到对话框（即捆绑或意图）的示例。然而，我所尝试的一切都不起作用。我不断收到NPE和

“找不到显式活动类”

错误。即使我用对话框构建一个超基本活动，它也不起作用。我必须在代码中添加什么才能使其工作

主要活动：

public class MainActivity extends AppCompatActivity {

  Button button;
  String textIWantToSee;

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

    button = (Button) findViewById(R.id.button);

    textIWantToSee = "If this is the text I want to pass form this activity to the Fragment";

    button.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {


        }
    });
  }
}

public class MainActivity extends AppCompatActivity {

TextView tvIntent;
Button button;
String textIWantToSee;

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

    tvIntent = (TextView) findViewById(R.id.tvIntent);
    button = (Button) findViewById(R.id.button);

    textIWantToSee = "If this is the text I want to pass form this activity to the Fragment";
    tvIntent.setText(textIWantToSee);

    button.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            String intent = String.valueOf(tvIntent);
            Intent intentToDialog = new Intent(MainActivity.this, Dialog.class);
            intentToDialog.putExtra("keyForIntent", intent);
            startActivity(intentToDialog); //Here is the exception

        }
    });
}

button.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
        LayoutInflater inflater = MainActivity.this.getLayoutInflater();
        View v = inflater.inflate(R.layout.dialog_layout, null);

        TextView textView = (TextView) v.findViewById(R.id.textView);
        textView.setText(textIWantToSee);

        AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);
        builder.setView(v);
        builder.show();

        }
    });

对话框：

public class Dialog extends DialogFragment {

  TextView textView;

  @Override
  public android.app.Dialog onCreateDialog(Bundle savedInstanceState) {

    LayoutInflater inflater = getActivity().getLayoutInflater();
    View v = inflater.inflate(R.layout.dialog_layout, null);

    textView = (TextView) v.findViewById(R.id.textView);

    AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
    builder.setView(v);

    return builder.create();
  }
}

更新

主要活动：

public class MainActivity extends AppCompatActivity {

  Button button;
  String textIWantToSee;

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

    button = (Button) findViewById(R.id.button);

    textIWantToSee = "If this is the text I want to pass form this activity to the Fragment";

    button.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {


        }
    });
  }
}

public class MainActivity extends AppCompatActivity {

TextView tvIntent;
Button button;
String textIWantToSee;

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

    tvIntent = (TextView) findViewById(R.id.tvIntent);
    button = (Button) findViewById(R.id.button);

    textIWantToSee = "If this is the text I want to pass form this activity to the Fragment";
    tvIntent.setText(textIWantToSee);

    button.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            String intent = String.valueOf(tvIntent);
            Intent intentToDialog = new Intent(MainActivity.this, Dialog.class);
            intentToDialog.putExtra("keyForIntent", intent);
            startActivity(intentToDialog); //Here is the exception

        }
    });
}

button.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
        LayoutInflater inflater = MainActivity.this.getLayoutInflater();
        View v = inflater.inflate(R.layout.dialog_layout, null);

        TextView textView = (TextView) v.findViewById(R.id.textView);
        textView.setText(textIWantToSee);

        AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);
        builder.setView(v);
        builder.show();

        }
    });

} 对话框：

}

舱单：

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="nl.blogvandetoekomst.passdatafromactivitytodialog">

<application
    android:allowBackup="true"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:supportsRtl="true"
    android:theme="@style/AppTheme">
    <activity android:name=".MainActivity">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
</application>

您可以直接在活动中创建对话框：

button.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
        LayoutInflater inflater = MainActivity.this.getLayoutInflater();
        View v = inflater.inflate(R.layout.dialog_layout, null);

        TextView textView = (TextView) v.findViewById(R.id.textView);
        textView.setText(textIWantToSee);

        AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);
        builder.setView(v);
        builder.show();

        }
    });

如果您使用的是支持库，则应使用android.support.v4.app.DialogFragment而不是android.app.Dialog。另外，你可以发布你用来显示对话框的部分代码吗

那么您必须使用DialogFragment的框架版本，正如OBX所指出的：

MainActivity.java

public class MainActivity extends AppCompatActivity {

    Button button;
    String textIWantToSee;

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

        button = (Button) findViewById(R.id.button); 

        textIWantToSee = "If this is the text I want to pass form this activity to the Fragment";

        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                Dialog dialogFragment = new Dialog();
                Bundle bundle = new Bundle();
                bundle.putString("TEXT",textIWantToSee);
                dialogFragment.setArguments(bundle);
                dialogFragment.show(getFragmentManager(),"Image Dialog");
            }
        });
    }
}

public class Dialog extends DialogFragment {

    TextView textView;

    @Override
    public android.app.Dialog onCreateDialog(Bundle savedInstanceState) {

        LayoutInflater inflater = getActivity().getLayoutInflater();
        View v = inflater.inflate(R.layout.dialog_layout, null);

        Bundle bundle = getArguments();
        String imageLink = bundle.getString("TEXT","");

        textView = (TextView) v.findViewById(R.id.textView);

        AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
        builder.setView(v);
        return builder.create();
    }
}

public class MainActivity extends AppCompatActivity {

Button button;
String textIWantToSee;

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

    button = (Button) findViewById(R.id.button);

    textIWantToSee = "If this is the text I want to pass form this activity to the Fragment";

    button.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {

            Dialog dialogFragment = new Dialog();
            Bundle bundle = new Bundle();
            bundle.putString("TEXT",textIWantToSee);
            dialogFragment.setArguments(bundle);
            dialogFragment.show((MainActivity.this).getSupportFragmentManager(),"Image Dialog");

        }
    });
}
}

public class Dialog extends DialogFragment {

TextView textView;

@Override
public android.app.Dialog onCreateDialog(Bundle savedInstanceState) {

    LayoutInflater inflater = getActivity().getLayoutInflater();
    View v = inflater.inflate(R.layout.dialog_layout, null);

    Bundle bundle = getArguments();
    String imageLink = bundle.getString("TEXT","");

    textView = (TextView) v.findViewById(R.id.textView);

    AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
    builder.setView(v);

    return builder.create();
}
}

Dialog.java

public class MainActivity extends AppCompatActivity {

    Button button;
    String textIWantToSee;

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

        button = (Button) findViewById(R.id.button); 

        textIWantToSee = "If this is the text I want to pass form this activity to the Fragment";

        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                Dialog dialogFragment = new Dialog();
                Bundle bundle = new Bundle();
                bundle.putString("TEXT",textIWantToSee);
                dialogFragment.setArguments(bundle);
                dialogFragment.show(getFragmentManager(),"Image Dialog");
            }
        });
    }
}

public class Dialog extends DialogFragment {

    TextView textView;

    @Override
    public android.app.Dialog onCreateDialog(Bundle savedInstanceState) {

        LayoutInflater inflater = getActivity().getLayoutInflater();
        View v = inflater.inflate(R.layout.dialog_layout, null);

        Bundle bundle = getArguments();
        String imageLink = bundle.getString("TEXT","");

        textView = (TextView) v.findViewById(R.id.textView);

        AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
        builder.setView(v);
        return builder.create();
    }
}

public class MainActivity extends AppCompatActivity {

Button button;
String textIWantToSee;

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

    button = (Button) findViewById(R.id.button);

    textIWantToSee = "If this is the text I want to pass form this activity to the Fragment";

    button.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {

            Dialog dialogFragment = new Dialog();
            Bundle bundle = new Bundle();
            bundle.putString("TEXT",textIWantToSee);
            dialogFragment.setArguments(bundle);
            dialogFragment.show((MainActivity.this).getSupportFragmentManager(),"Image Dialog");

        }
    });
}
}

public class Dialog extends DialogFragment {

TextView textView;

@Override
public android.app.Dialog onCreateDialog(Bundle savedInstanceState) {

    LayoutInflater inflater = getActivity().getLayoutInflater();
    View v = inflater.inflate(R.layout.dialog_layout, null);

    Bundle bundle = getArguments();
    String imageLink = bundle.getString("TEXT","");

    textView = (TextView) v.findViewById(R.id.textView);

    AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
    builder.setView(v);

    return builder.create();
}
}

这种方法对我来说非常有效

编辑：

在onClick中执行此操作时：

Intent intentToDialog = new Intent(MainActivity.this, Dialog.class);
intentToDialog.putExtra("keyForIntent", intent);
startActivity(intentToDialog); //Here is the exception

您没有启动活动，Dialog.class是扩展的DialogFragment，无法显示启动活动的对话框。请尝试我发布的最后一个代码。

这是从

活动向对话框片段
传递数据的方式：
MainActivity.java
public class MainActivity extends AppCompatActivity {

    Button button;
    String textIWantToSee;

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

        button = (Button) findViewById(R.id.button); 

        textIWantToSee = "If this is the text I want to pass form this activity to the Fragment";

        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                Dialog dialogFragment = new Dialog();
                Bundle bundle = new Bundle();
                bundle.putString("TEXT",textIWantToSee);
                dialogFragment.setArguments(bundle);
                dialogFragment.show(getFragmentManager(),"Image Dialog");
            }
        });
    }
}

public class Dialog extends DialogFragment {

    TextView textView;

    @Override
    public android.app.Dialog onCreateDialog(Bundle savedInstanceState) {

        LayoutInflater inflater = getActivity().getLayoutInflater();
        View v = inflater.inflate(R.layout.dialog_layout, null);

        Bundle bundle = getArguments();
        String imageLink = bundle.getString("TEXT","");

        textView = (TextView) v.findViewById(R.id.textView);

        AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
        builder.setView(v);
        return builder.create();
    }
}

public class MainActivity extends AppCompatActivity {

Button button;
String textIWantToSee;

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

    button = (Button) findViewById(R.id.button);

    textIWantToSee = "If this is the text I want to pass form this activity to the Fragment";

    button.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {

            Dialog dialogFragment = new Dialog();
            Bundle bundle = new Bundle();
            bundle.putString("TEXT",textIWantToSee);
            dialogFragment.setArguments(bundle);
            dialogFragment.show((MainActivity.this).getSupportFragmentManager(),"Image Dialog");

        }
    });
}
}

public class Dialog extends DialogFragment {

TextView textView;

@Override
public android.app.Dialog onCreateDialog(Bundle savedInstanceState) {

    LayoutInflater inflater = getActivity().getLayoutInflater();
    View v = inflater.inflate(R.layout.dialog_layout, null);

    Bundle bundle = getArguments();
    String imageLink = bundle.getString("TEXT","");

    textView = (TextView) v.findViewById(R.id.textView);

    AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
    builder.setView(v);

    return builder.create();
}
}

Dialog.java
public class MainActivity extends AppCompatActivity {

    Button button;
    String textIWantToSee;

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

        button = (Button) findViewById(R.id.button); 

        textIWantToSee = "If this is the text I want to pass form this activity to the Fragment";

        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                Dialog dialogFragment = new Dialog();
                Bundle bundle = new Bundle();
                bundle.putString("TEXT",textIWantToSee);
                dialogFragment.setArguments(bundle);
                dialogFragment.show(getFragmentManager(),"Image Dialog");
            }
        });
    }
}

public class Dialog extends DialogFragment {

    TextView textView;

    @Override
    public android.app.Dialog onCreateDialog(Bundle savedInstanceState) {

        LayoutInflater inflater = getActivity().getLayoutInflater();
        View v = inflater.inflate(R.layout.dialog_layout, null);

        Bundle bundle = getArguments();
        String imageLink = bundle.getString("TEXT","");

        textView = (TextView) v.findViewById(R.id.textView);

        AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
        builder.setView(v);
        return builder.create();
    }
}

public class MainActivity extends AppCompatActivity {

Button button;
String textIWantToSee;

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

    button = (Button) findViewById(R.id.button);

    textIWantToSee = "If this is the text I want to pass form this activity to the Fragment";

    button.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {

            Dialog dialogFragment = new Dialog();
            Bundle bundle = new Bundle();
            bundle.putString("TEXT",textIWantToSee);
            dialogFragment.setArguments(bundle);
            dialogFragment.show((MainActivity.this).getSupportFragmentManager(),"Image Dialog");

        }
    });
}
}

public class Dialog extends DialogFragment {

TextView textView;

@Override
public android.app.Dialog onCreateDialog(Bundle savedInstanceState) {

    LayoutInflater inflater = getActivity().getLayoutInflater();
    View v = inflater.inflate(R.layout.dialog_layout, null);

    Bundle bundle = getArguments();
    String imageLink = bundle.getString("TEXT","");

    textView = (TextView) v.findViewById(R.id.textView);

    AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
    builder.setView(v);

    return builder.create();
}
}

您的对话框片段需要一个宿主活动，它需要在活动中膨胀
要在MainActivity中充气/显示DialogFragment，请使用：
button.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {
        Bundle bundle = new Bundle(); //Bundle containing data you are passing to the dialog
        bundle.putString("text", textIWantToSee);

        Dialog dialog = new Dialog(); //Create a new Dialog
        dialog.setArguments(bundle);

        dialog.show(getSupportFragmentManager(), "MY_DIALOG_TAG"); //Inflate the dialog
    }
});

使用对话框片段的新实例。
参考：
如果您使用的是kotlin，请尝试在伴生对象中定义newInstance
companion object {
        fun newInstance(num: Int): MyDialogFragment{
            val f = DimensionDialogFragment()
            val args = Bundle()
            args.putInt("num", num)
            f.setArguments(args)

            return f
        }
    }

请问，你的活动名称是什么？可能重复：我有两门课：1。主要活动；2.对话框。@AndroidRuntimeException:我知道还有其他例子。但关键是我无法让它工作，即使是在上面这样的超级基本程序中。我不明白我必须把那段代码放在哪里，而不会出现诸如“无法解析方法”等错误。您在清单中定义了活动了吗？请添加stacktrace错误。由于所有明显的原因，这是一种不好的方法，DialogFragment
是推荐的方法，这给了我“无法解析方法'GetLayoutFlater（）'”，“变量'v'已在范围中定义”，并且无法应用Builder中的生成器（android.content.Context）（匿名android.view.view.OnClickListener）。你的活动名称是什么？我有两个类：1.MainActivity；2.Dialog。当我在=充气机
前面更改view v
时，它会工作。对于myVariable
它会工作，因为v已经在范围内定义了。非常感谢！这让我感到非常高兴无法解析（（MainActivity.this.getSupportFragmentManager（），“图像对话框”）处的“show（android.support.v4.app.FragmentManager，java.lang.String）”方法；您使用的是哪个片段，是片段还是v4片段？'android.support.v7.app.AlertDialog；'已导入。我手动导入了'android.support.v4.app.FragmentManager；'，但该片段保持灰色。当我手动导入它时，“导入android.support.v4.app.FragmentManager；“保持灰色。我没有显示对话框的特定代码。我尝试了捆绑和意图。类似于：“startActivity（intentToDialog）；”和“new dialog（）.show（getFragmentManager（），“dialog”）；。OP介绍了如何将数据从“活动”传递到DialogFragment，而不是从FragmentActivity传递到DialogActivity。”。