我目前正在开发我的大学GPA跟踪器应用程序（我是新手开发人员）。该应用程序的主页在纵向模式下运行良好，但我有几个关于我的应用程序的问题。我感谢所有的帮助。
我知道onSavedInstance之前已在这里得到解答，但我不知道如何将它合并到我的代码中。我不只是在寻找答案。如果有人能向我解释，我真的很感激。旋转时我的所有观点都会丢失，我知道这是由onSavedInstanceState引起的。
当方向发生变化时，我发现3列的网格布局更合适。用于（最多）8个按钮的2个列和用于floatActionButton的右侧的最后一列，因此我为横向创建了一个单独的xml目录和文件。我认为布局工作正常，但由于我在第82行遇到的问题，它不会每次都填充和崩溃（我按照文档说明但是它说它无法运行我归因于我的方法的onClick方法FAB on xml）。
我的floatActionButton，当向下滚动应用程序时，向下移动应用程序。每次我滚动布局或单击它以添加更多视图时，FAB就会下降。
我创建了2个if语句来处理每个方向更改的动态视图添加但我最后重复代码并且Java看起来像一团糟。
我很抱歉向您提供了如此混乱的代码。
我的横向xml文件
<?xml version="1.0" encoding="utf-8"?>
<ScrollView
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_height="match_parent"
android:layout_width="match_parent"
android:fillViewport="true"
>
<GridLayout
android:id="@+id/semester_grid_layout"
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:background="#FFFFFF"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:columnCount="3"
android:rowCount="4"
xmlns:app="http://schemas.android.com/apk/res-auto"
tools:context="myapp.onur.journeygpacalculator.MainActivity">
<android.support.design.widget.FloatingActionButton
android:id="@+id/addActionButton"
android:layout_column="2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_margin="16dp"
android:clickable="true"
android:onClick="onFloatActionButtonClick"
android:longClickable="true"
app:backgroundTint="@color/colorPrimary"
android:tint="@color/colorWhite"
app:borderWidth="0dp"
android:src="@drawable/ic_add_black_48dp" />
</GridLayout>
</ScrollView>
我的常规xml布局
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
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="wrap_content"
android:background="#FFFFFF"
tools:context="myapp.onur.journeygpacalculator.MainActivity">
<ScrollView
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fillViewport="true"
>
<LinearLayout
android:id="@+id/main_layout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:padding="6dp">
</LinearLayout>
</ScrollView>
<android.support.design.widget.FloatingActionButton
android:id="@+id/addActionButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_alignParentEnd="true"
android:layout_margin="16dp"
android:clickable="true"
android:longClickable="true"
android:onClick="onFloatActionButtonClick"
android:src="@drawable/ic_add_black_48dp"
android:tint="@color/colorWhite"
app:backgroundTint="@color/colorPrimary"
android:elevation="6dp"
app:borderWidth="0dp"/>
</RelativeLayout>
我的主要活动
public class MainActivity extends AppCompatActivity {
int counter = 0;
FloatingActionButton addingSemester;
Button semesterButton;
LinearLayout semesterLayout;
GridLayout semesterGridLayout;
RelativeLayout.LayoutParams lp = new RelativeLayout.LayoutParams(
AppBarLayout.LayoutParams.MATCH_PARENT,
AppBarLayout.LayoutParams.WRAP_CONTENT);
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
addingSemester = (FloatingActionButton) findViewById(R.id.addActionButton);
semesterLayout = (LinearLayout) findViewById(R.id.main_layout);
semesterGridLayout = (GridLayout)findViewById(R.id.semester_grid_layout);
semesterButton = new Button(MainActivity.this);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
MenuInflater menuInflater = getMenuInflater();
menuInflater.inflate(R.menu.main, menu);
return super.onCreateOptionsMenu(menu);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
int id = item.getItemId();
if (id == R.id.delete) {
new AlertDialog.Builder(MainActivity.this)
.setTitle("Delete entry")
.setMessage("Are you sure you want to delete everything?")
.setCancelable(true)
.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
semesterLayout.removeAllViews();
counter = 0;
}
})
.setNegativeButton("No", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
dialog.cancel();
}
})
.show();
return true;
}
return super.onOptionsItemSelected(item);
}
public void onFloatActionButtonClick(View view) {
float screenRotation = semesterLayout.getOrientation();
semesterButton = new Button(MainActivity.this);
if (counter < 8) {
semesterButton.setId(counter + 1);
semesterButton.setText("Semester " + (counter + 1));
semesterButton.setBackgroundColor(getColor(R.color.colorPrimary));
semesterButton.setTextColor(Color.WHITE);
lp.setMargins(24, 24, 24, 24);
semesterButton.setLayoutParams(lp);
if(screenRotation == Surface.ROTATION_0 || screenRotation == Surface.ROTATION_180){
semesterGridLayout.addView(semesterButton);
counter++;
semesterButton.setOnLongClickListener(new View.OnLongClickListener() {
@Override
public boolean onLongClick(View v) {
final Button b = (Button) v;
b.setTag(b.getText().toString());
b.setBackgroundColor(Color.RED);
b.setText("Delete");
new AlertDialog.Builder(MainActivity.this)
.setTitle("Delete entry")
.setMessage("Are you sure you want to delete this entry?")
.setCancelable(true)
.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
semesterGridLayout.removeView(b);
counter--;
for (int i = 0; i < semesterGridLayout.getChildCount(); i++) {
((Button) semesterGridLayout.getChildAt(i)).setText("Semester " + (i + 1));
}
}
})
.setNegativeButton("No", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
b.cancelLongPress();
b.setBackgroundColor(ContextCompat.getColor(MainActivity.this, R.color.colorPrimary));
b.setText(b.getTag().toString());
dialog.cancel();
}
})
.show();
return true;
}
});
}else if(screenRotation == Surface.ROTATION_90){
semesterLayout.addView(semesterButton);
counter++;
semesterButton.setOnLongClickListener(new View.OnLongClickListener() {
@Override
public boolean onLongClick(View v) {
final Button b = (Button) v;
b.setTag(b.getText().toString());
b.setBackgroundColor(Color.RED);
b.setText("Delete");
new AlertDialog.Builder(MainActivity.this)
.setTitle("Delete entry")
.setMessage("Are you sure you want to delete this entry?")
.setCancelable(true)
.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
semesterLayout.removeView(b);
counter--;
for (int i = 0; i < semesterLayout.getChildCount(); i++) {
((Button) semesterLayout.getChildAt(i)).setText("Semester " + (i + 1));
}
}
})
.setNegativeButton("No", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
b.cancelLongPress();
b.setBackgroundColor(ContextCompat.getColor(MainActivity.this, R.color.colorPrimary));
b.setText(b.getTag().toString());
dialog.cancel();
}
})
.show();
return true;
}
});
}
} else if (counter == 8) {
Toast.makeText(MainActivity.this, "You cannot add more than 8 semesters", Toast.LENGTH_SHORT).show();
}
}
}
答案 0 :(得分：0)
在回应第4项时，如果您将相同的代码块（或与参数类似的代码）重构为私有方法，您会发现代码更易于阅读和理解。此外，如果对if语句的两个路径执行代码，则可以将该代码移到外面：
public void onFloatActionButtonClick(View view) {
float screenRotation = semesterLayout.getOrientation();
semesterButton = new Button(MainActivity.this);
if (counter < 8) {
semesterButton.setId(counter + 1);
semesterButton.setText("Semester " + (counter + 1));
semesterButton.setBackgroundColor(getColor(R.color.colorPrimary));
semesterButton.setTextColor(Color.WHITE);
lp.setMargins(24, 24, 24, 24);
semesterButton.setLayoutParams(lp);
if (screenRotation == Surface.ROTATION_0 || screenRotation == Surface.ROTATION_180) {
semesterGridLayout.addView(semesterButton);
} else if (screenRotation == Surface.ROTATION_90) {
semesterLayout.addView(semesterButton);
}
// these lines moved outside the if statement blocks
counter++;
setOnLongClickListenerForSemesterButton();
} else if (counter == 8) {
Toast.makeText(MainActivity.this, "You cannot add more than 8 semesters", Toast.LENGTH_SHORT).show();
}
}
// this method refactored from the duplicated code
private void setOnLongClickListenerForSemesterButton() {
semesterButton.setOnLongClickListener(new View.OnLongClickListener() {
@Override
public boolean onLongClick(View v) {
final Button b = (Button) v;
b.setTag(b.getText().toString());
b.setBackgroundColor(Color.RED);
b.setText("Delete");
new AlertDialog.Builder(MainActivity.this)
.setTitle("Delete entry")
.setMessage("Are you sure you want to delete this entry?")
.setCancelable(true)
.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
semesterGridLayout.removeView(b);
counter--;
for (int i = 0; i < semesterGridLayout.getChildCount(); i++) {
((Button) semesterGridLayout.getChildAt(i)).setText("Semester " + (i + 1));
}
}
})
.setNegativeButton("No", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
b.cancelLongPress();
b.setBackgroundColor(ContextCompat.getColor(MainActivity.this, R.color.colorPrimary));
b.setText(b.getTag().toString());
dialog.cancel();
}
})
.show();
return true;
}
});
}