Question

我有一个应用程序，包含几个嵌套在ScrollViews中的TextView，每个TextView包含几千个单词。

我希望用户能够阅读TextView的一部分然后离开屏幕（甚至关闭应用程序）并能够返回到他们离开的地方。

我尝试在TextView的活动中使用onPause()和onResume()，但它没有用。

StoryBodyActivity：

public class StoryBodyActivity extends AppCompatActivity {

    private TextView storyBodyTextView;
    private ScrollView storyBodyScrollView;
    private int storyID;
    Parcelable state;

    int scrollY = 0;

    @Override
    public void onPause() {
        Log.d("pause", "saving listview state @ onPause");
        state = storyBodyTextView.onSaveInstanceState();
        scrollY = storyBodyScrollView.getScrollY();
        super.onPause();
    }

    @Override
    public void onResume() {
        storyBodyScrollView.post(new Runnable() {
            @Override
            public void run() {
                storyBodyScrollView.scrollTo(0, scrollY);
            }
        });
        super.onResume();
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.menu_story_body, menu);
        return true;
    }

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

        Bundle extras = getIntent().getExtras();

        String story = extras.getString("story");
        int storyID = extras.getInt("story_id");
        Log.i("stories", Integer.toString(storyID));

        setTitle(story);

        storyBodyTextView = (TextView) findViewById(R.id.story_body_text_view);
        storyBodyScrollView = (ScrollView) findViewById(R.id.story_body_scroll_view);

        DatabaseHelper db = new DatabaseHelper(this);

        String storyBody = db.getStoryBody(storyID);

        storyBodyTextView.setText(Html.fromHtml(storyBody));

        if(state != null) {
            Log.d("pause", "trying to restore textview state..");
            storyBodyTextView.onRestoreInstanceState(state);
        }

    }
}

DatabaseHelper的一个片段：

public String getStoryBody(int storyID) {

        String storyBody = "";

        // Select all query
        String selectQuery = "SELECT body FROM " + BOOKS + " WHERE id = '" + storyID + "'";

        SQLiteDatabase db = this.getWritableDatabase();
        Cursor cursor = db.rawQuery(selectQuery, null);

        // looping through all rows and adding to list
        if (cursor.moveToFirst()) {
            do {
                storyBody = cursor.getString(0);
            } while (cursor.moveToNext());
        }
        return storyBody;
    }

activity_story_body：

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.example.apple.bookshelf.StoryBodyActivity">

    <ScrollView
        android:id="@+id/story_body_scroll_view"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:scrollbars="vertical"
        android:fillViewport="true">

    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:gravity="start|top"
        android:paddingLeft="20dp"
        android:paddingRight="20dp"
        android:paddingBottom="80dp"
        android:textSize="16sp"
        android:lineSpacingExtra="5dp"
        android:id="@+id/story_body_text_view" />

    </ScrollView>

</android.support.constraint.ConstraintLayout>

Answer 1

您需要在数据库或共享偏好设置中保存scrollY并在onCreate()

中检索该值

Answer 2

onPause和onResume仅在应用未被销毁之前。在这里你完全关闭应用程序，所以应用程序是destroyed。因此，您可以尝试保留shared preferences中的值，并在onCreate中设置位置。我希望我的回答很有帮助。

应用程序关闭后，请记住ScrollView的位置

2 个答案: