使用SQLite：Android Studio将数据从一个活动传输到另一个活动
我有一个“Track Walk”页面，用于计算用户的步数。我的目的是累积这些步骤，然后在另一个Activity中显示“Total”。 Track walk页面包含一个“End Walk”按钮。单击时将计数器重置为0会很好，然后将总计步骤添加到总计数器。
我将致力于自己的解决方案，但也希望在此处发布以获得一些指导。谢谢！
以下是Track Walk活动：
public class trackWalk extends AppCompatActivity implements SensorEventListener {
SensorManager sensorManager;
TextView tv_steps;
boolean running = false;
SQLiteDatabase db;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_track_walk);
db=openOrCreateDatabase("STEPSTAKEN", Context.MODE_PRIVATE, null);
db.execSQL("CREATE TABLE IF NOT EXISTS STEPS_TABLE(steps INTEGER);");
tv_steps = (TextView) findViewById(R.id.steps);
sensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE);
button = findViewById(R.id.trackWalk);
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
//Reset counter and Populate Total Value in "Walk History"
}
});
}
@Override
protected void onResume() {
super.onResume();
running=true;
Sensor countSensor = sensorManager.getDefaultSensor(Sensor.TYPE_STEP_COUNTER);
if(countSensor != null) {
sensorManager.registerListener(this, countSensor, SensorManager.SENSOR_DELAY_UI);
}
else {
Toast.makeText(this, "Please enable Sensor!", Toast.LENGTH_SHORT).show();
}
}
@Override
protected void onPause() {
super.onPause();
running = false;
// Unregistering will stop steps
// sensorManager.unregisterListener(this);
}
@Override
public void onSensorChanged(SensorEvent event) {
if(running) {
tv_steps.setText(String.valueOf(event.values[0]));
db.execSQL("INSERT INTO STEPS_TABLE VALUES('"+tv_steps.getText()+"');");
}
}
@Override
public void onAccuracyChanged(Sensor sensor, int accuracy) {
}
}
以下是“行走历史”页面，其中累积值应为：
package edu.phoenix.mbl402.walkmypup;
import android.support.v7.app.AppCompatActivity; import android.os.Bundle;
public class walkHistory extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_walk_history);
}
}
3 个答案:
答案 0 :(得分：1)
您可以使用Intents执行此操作。将值与所需参数一起传递，并将其置于下一个活动中。
答案 1 :(得分：1)
我建议稍作修改，这可能会让您更好地利用数据。
这不是使用
db.execSQL("CREATE TABLE IF NOT EXISTS STEPS_TABLE(steps INTEGER);");
.........
db.execSQL("INSERT INTO STEPS_TABLE VALUES('"+tv_steps.getText()+"');");
使用
db.execSQL("CREATE TABLE IF NOT EXISTS STEPS_TABLE(steps INTEGER, timestamp TEXT DEFAULT CURRENT_TIMESTAMP);");
.........
db.execSQL("INSERT INTO STEPS_TABLE (steps) VALUES('"+tv_steps.getText()+"');");
也在改变： -
因此而不是拥有如下数据： -
除了两次更改之外，您将获得以下数据： -
- 请注意，两者的上述数据是随机生成的，但在很短的时间内因此日期/时间相同。
关于将信息传递给另一个活动，基本上没有必要表格包含所有内容，因此只需查询新活动中的表格。
工作示例
以下示例基于您的代码。为了方便起见，我添加了一个模拟传感器更改的按钮和方法，当点击按钮时会添加一个随机数量的步骤。
代码中的注释希望能够解释代码。
TrackWalk **
public class TrackWalk extends AppCompatActivity implements SensorEventListener {
//<<<<<<<<<< Use single source (constants) for DB related names
public static final String DBNAME = "STEPSTAKEN";
public static final String TB_STEPSTAKEN = "stepstaken";
public static final String COL_STEPSTAKEN_STEPS = "steps";
public static final String COl_STEPSTAKEN_TIMESTAMP = "timestamp";
SensorManager sensorManager;
TextView tv_steps;
boolean running = false;
SQLiteDatabase db;
Button button, sensor; //<<<< Added another button to mimic sensor change
Random rnd; //<<<<< For creating random number of steps
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
rnd = new Random();
//<<<<<<<<<< Note changes to use constants
db=openOrCreateDatabase(DBNAME, Context.MODE_PRIVATE, null); //
db.execSQL(
"CREATE TABLE IF NOT EXISTS " +
TB_STEPSTAKEN +
"(" +
COL_STEPSTAKEN_STEPS + " INTEGER, " +
COl_STEPSTAKEN_TIMESTAMP + " TEXT DEFAULT CURRENT_TIMESTAMP" +
")"
);
tv_steps = (TextView) findViewById(R.id.steps);
sensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE);
//<<<<<<<<<< Added to mimic sensor change at button click
sensor = this.findViewById(R.id.sensor);
sensor.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
noSensor(); //<<<< Mimic sensor change
}
});
button = findViewById(R.id.trackWalk);
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
//Reset counter and Populate Total Value in "Walk History"
Intent i = new Intent(getBaseContext(),WalkHistory.class); //<<<< ready to start activity
startActivity(i); // start the WalkHistory Activity
}
});
}
@Override
protected void onResume() {
super.onResume();
running=true;
Sensor countSensor = sensorManager.getDefaultSensor(Sensor.TYPE_STEP_COUNTER);
if(countSensor != null) {
sensorManager.registerListener(this, countSensor, SensorManager.SENSOR_DELAY_UI);
}
else {
Toast.makeText(this, "Please enable Sensor!", Toast.LENGTH_SHORT).show();
}
}
@Override
protected void onPause() {
super.onPause();
running = false;
// Unregistering will stop steps
// sensorManager.unregisterListener(this);
}
@Override
public void onSensorChanged(SensorEvent event) {
if(running) {
tv_steps.setText(String.valueOf(event.values[0]));
db.execSQL("INSERT INTO STEPS_TABLE VALUES('"+tv_steps.getText()+"');");
}
}
//<<<<<<<<<< MIMIC SENSOR for testing >>>>>>>>>>
public void noSensor() {
db.execSQL("INSERT INTO " + TB_STEPSTAKEN +
"(" + COL_STEPSTAKEN_STEPS + ")" +
"VALUES("+String.valueOf(rnd.nextInt(10000-1 + 1)+1) +");");
}
@Override
public void onAccuracyChanged(Sensor sensor, int accuracy) {
}
}
activity_walk_history.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
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:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="@string/appbar_scrolling_view_behavior"
tools:context=".WalkHistory"
tools:showIn="@layout/activity_walk_history">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Total Steps "
/>
<TextView
android:id="@+id/totalsteps"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
/>
<ListView
android:id="@+id/walkhistorylist"
android:layout_width="match_parent"
android:layout_height="wrap_content">
</ListView>
</LinearLayout>
WalkHistory
public class WalkHistory extends AppCompatActivity {
Cursor mCsr;
SQLiteDatabase mDB;
SimpleCursorAdapter mSCA;
ListView mLV;
TextView mTotalSteps;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_walk_history);
mLV = this.findViewById(R.id.walkhistorylist);
mTotalSteps = this.findViewById(R.id.totalsteps);
String total_steps_column_name = "total_steps";
// As Cursor Adpaters need _id column grab an alias of thr rowid as _id
String[] columns = new String[]{"rowid AS " + BaseColumns._ID + ",*"};
// Get the database
mDB = this.openOrCreateDatabase(TrackWalk.DBNAME, MODE_PRIVATE,null);
// Extract Data (all) into a Cursor)
mCsr = mDB.query(
TrackWalk.TB_STEPSTAKEN,
columns,
null,
null,
null,
null,
TrackWalk.COl_STEPSTAKEN_TIMESTAMP + " DESC"
);
// Setup the Adapter for the ListView
mSCA = new SimpleCursorAdapter(this,android.R.layout.simple_list_item_2,mCsr,
new String[]{"timestamp","steps"},
new int[]{android.R.id.text1, android.R.id.text2},
0
);
// Tie the Adapter to the Listview
mLV.setAdapter(mSCA);
// Get the sum of the Steps (note would use the same WHERE clause as the ListView Cursor)
Cursor csr = mDB.query(
TrackWalk.TB_STEPSTAKEN,
new String[]{
"sum(steps) AS " + total_steps_column_name
},
null,
null,
null,
null,
null
);
// Apply the sum of the steps to the TextView
if (csr.moveToFirst()) {
mTotalSteps.setText(csr.getString(csr.getColumnIndex(total_steps_column_name)));
}
}
}
结果
以下是单击按钮转到WalkHistory活动（添加一些数据后）的结果示例。列出了条目。该列表前面是总步数。
可以看出，无需将TrackWalk活动中的任何信息传递给WalkHistory活动。
附加多个行走/重置计数器（排序）
如果您想保留历史记录，并且历史记录按钮是Walk Ended按钮。那么也许以下就足够了（至少可能作为一个起点）。基本上这适用于“当前行走”的概念，启动应用程序并假定“当前行走”并且在单击历史记录按钮时假定结束，此时仅显示该步行的那些步骤以及该行走的总计。
返回时（后退按钮）会假设一个新的Walk，等等。
这利用第二张桌子作为步行，其中3列id日期/时间，当开始日期/时间结束时但重要的是空白直至结束。
第一个表添加了另一个列，walk列是相应walk的id。
当应用程序启动或恢复（从WalkHistory活动返回）时，如果有任何步行（应该只有1）在walkended列中没有日期/时间，则该步行被视为当前步行。否则插入当前行走行（walkended列为空）。在这两种情况下，mCurrentWalk变量都设置为相应的 id 。
每条记录都包含拥有的walkid。单击“历史记录”按钮时，mCurrentlWalk值将通过一个额外的意图发送到WalkHistory活动。 WalkHistory活动获取此值并相应地设置相应的命名变量，并使用它来选择列表中显示的相应行以及确定总数时。 new是一个用当前日期时间更新walk行的调用，因此有效地将行（aka walk）标记为结束。
所以这里改变了 TrackWalk 活动“： -
public class TrackWalk extends AppCompatActivity implements SensorEventListener {
//<<<<<<<<<< Use single source (constants) for DB related names
public static final String DBNAME = "STEPSTAKEN";
public static final String TB_STEPSTAKEN = "stepstaken";
public static final String COL_STEPSTAKEN_STEPS = "steps";
public static final String COl_STEPSTAKEN_TIMESTAMP = "timestamp";
public static final String COL_STEPSTAKEN_WALK = "walk";
public static final String TB_WALKS = "walks";
public static final String COL_WALKID = "walkid";
public static final String COL_WALKSTARTED = "walkstarted";
public static final String COL_WALKENDED = "walkended";
// used for passing data
public static final String INTENTEXTRA_WALKID = "ie_walkid";
SensorManager sensorManager;
TextView tv_steps;
boolean running = false;
SQLiteDatabase db;
Button button, sensor; //<<<< Added another button to mimic sensor change
Random rnd; //<<<<< For creating random number of steps
long mCurrentWalk;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
rnd = new Random();
//<<<<<<<<<< Note changes to use constants
db=openOrCreateDatabase(DBNAME, Context.MODE_PRIVATE, null); //
db.execSQL(
"CREATE TABLE IF NOT EXISTS " +
TB_STEPSTAKEN +
"(" +
COL_STEPSTAKEN_STEPS + " INTEGER, " +
COl_STEPSTAKEN_TIMESTAMP + " TEXT DEFAULT CURRENT_TIMESTAMP," +
COL_STEPSTAKEN_WALK + " INTEGER " + //<<<< ADDED FOR multiple walks
")"
);
// Create a Walks table
String crt_walks_table = "CREATE TABLE IF NOT EXISTS " +
TB_WALKS +
"(" +
COL_WALKID + " INTEGER PRIMARY KEY AUTOINCREMENT, " +
COL_WALKSTARTED + " TEXT DEFAULT CURRENT_TIMESTAMP, " +
COL_WALKENDED + " TEXT DEFAULT ''" +
")";
db.execSQL(crt_walks_table);
tv_steps = (TextView) findViewById(R.id.steps);
sensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE);
//<<<<<<<<<< Added to mimic sensor change at button click
sensor = this.findViewById(R.id.sensor);
sensor.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
noSensor(); //<<<< Mimic sensor change
}
});
button = findViewById(R.id.trackWalk);
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
//Reset counter and Populate Total Value in "Walk History"
Intent i = new Intent(getBaseContext(),WalkHistory.class); //<<<< ready to start activity
i.putExtra(INTENTEXTRA_WALKID,mCurrentWalk);
startActivity(i); // start the WalkHistory Activity
}
});
setCurrentWalk(); //<<<< Set the current walk (utilises last if not ended)
}
@Override
protected void onResume() {
super.onResume();
running=true;
Sensor countSensor = sensorManager.getDefaultSensor(Sensor.TYPE_STEP_COUNTER);
if(countSensor != null) {
sensorManager.registerListener(this, countSensor, SensorManager.SENSOR_DELAY_UI);
}
else {
Toast.makeText(this, "Please enable Sensor!", Toast.LENGTH_SHORT).show();
}
setCurrentWalk();
}
@Override
protected void onPause() {
super.onPause();
running = false;
// Unregistering will stop steps
// sensorManager.unregisterListener(this);
}
@Override
public void onSensorChanged(SensorEvent event) {
if(running) {
tv_steps.setText(String.valueOf(event.values[0]));
db.execSQL("INSERT INTO STEPS_TABLE VALUES('"+tv_steps.getText()+"');");
}
}
//<<<<<<<<<< MIMIC SENSOR for testing >>>>>>>>>>
public void noSensor() {
db.execSQL("INSERT INTO " + TB_STEPSTAKEN +
"(" +
COL_STEPSTAKEN_STEPS +
"," +
COL_STEPSTAKEN_WALK +
")" +
"VALUES(" +
String.valueOf(rnd.nextInt(10000-1 + 1)+1)
+
"," +
String.valueOf(mCurrentWalk) +
");");
}
@Override
public void onAccuracyChanged(Sensor sensor, int accuracy) {
}
private void setCurrentWalk() {
mCurrentWalk = -1;
String whereclause = "length(" + COL_WALKENDED + ") < 1"; // Only walks that haven't been ended
// Is there an unfished walk?? if so use that
Cursor csr = db.query(TB_WALKS,null,whereclause,null,null,null,COL_WALKID + " DESC");
if (csr.moveToFirst()) {
mCurrentWalk = csr.getLong(csr.getColumnIndex(COL_WALKID)); //<<<< use incomplete walk
}
csr.close();
// If there is no unfinished walk then create a new walk
if (mCurrentWalk < 1) {
String insrtsql = "INSERT INTO " + TB_WALKS +
" (" +
COL_WALKID +
") VALUES(null)";
db.execSQL(insrtsql);
mCurrentWalk = DatabaseUtils.longForQuery(db,"SELECT last_insert_rowid()",null);
}
}
}
这是改变后的 WalkHistory 活动： -
public class WalkHistory extends AppCompatActivity {
Cursor mCsr;
SQLiteDatabase mDB;
SimpleCursorAdapter mSCA;
ListView mLV;
TextView mTotalSteps;
long mCurrentWalk;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_walk_history);
// Get the current walk id
mCurrentWalk = this.getIntent().getLongExtra(TrackWalk.INTENTEXTRA_WALKID,-1);
mLV = this.findViewById(R.id.walkhistorylist);
mTotalSteps = this.findViewById(R.id.totalsteps);
String total_steps_column_name = "total_steps";
// As Cursor Adpaters need _id column grab an alias of thr rowid as _id
String[] columns = new String[]{"rowid AS " + BaseColumns._ID + ",*"};
// Get the database
mDB = this.openOrCreateDatabase(TrackWalk.DBNAME, MODE_PRIVATE,null);
// Set the current walk as ended
setCurrentWalkEnded();
String whereclause = TrackWalk.COL_STEPSTAKEN_WALK + "=?";
String[] whereargs = new String[]{String.valueOf(mCurrentWalk)};
// Extract Data for this walk
mCsr = mDB.query(
TrackWalk.TB_STEPSTAKEN,
columns,
whereclause,
whereargs,
null,
null,
TrackWalk.COl_STEPSTAKEN_TIMESTAMP + " DESC"
);
// Setup the Adapter for the ListView
mSCA = new SimpleCursorAdapter(this,android.R.layout.simple_list_item_2,mCsr,
new String[]{"timestamp","steps"},
new int[]{android.R.id.text1, android.R.id.text2},
0
);
// Tie the Adapter to the Listview
mLV.setAdapter(mSCA);
// Get the sum of the Steps (note would use the same WHERE clause as the ListView Cursor)
Cursor csr = mDB.query(
TrackWalk.TB_STEPSTAKEN,
new String[]{
"sum(steps) AS " + total_steps_column_name
},
whereclause,
whereargs,
null,
null,
null
);
// Apply the sum of the steps to the TextView
if (csr.moveToFirst()) {
mTotalSteps.setText(csr.getString(csr.getColumnIndex(total_steps_column_name)));
}
}
/**
* Set the current walk as ended, but only if some records exist
*/
private void setCurrentWalkEnded() {
String whereclause1 = TrackWalk.COL_STEPSTAKEN_WALK + "=?";
String[] whereargs = new String[]{String.valueOf(mCurrentWalk)};
Cursor csr = mDB.query(TrackWalk.TB_STEPSTAKEN,null,whereclause1,whereargs,null,null,null);
String whereclause2 = TrackWalk.COL_WALKID + "=?";
if (csr.getCount() > 0 ) {
String updtsql = "UPDATE " + TrackWalk.TB_WALKS + " SET " + TrackWalk.COL_WALKENDED + " = datetime('now') WHERE " + whereclause2;
mDB.execSQL(updtsql, whereargs);
}
csr.close();
}
}
- 注意这尚未经过广泛测试，并且非常简陋。
答案 2 :(得分：0)
您可以使用意图来实现此目的，如上面的评论中所述。 但是，您也可以通过SQLite检索数据。
因此，当结束步行按钮结束时，您可以开始新的活动：
Intent intent = new Intent(trackWalk.this,walkHistory.class);
startActivity(intent);
然后在处理SQLite的类上：
public Cursor fetchData() {
Cursor c = this.database.query(SQLiteHelper.YOUR_TABLE_NAME,new String[]{SQLiteHelper.YOR_COLUMN}, null, null, null, null, null);
if (c != null) {
c.moveToFirst();
}
return c;
}
您可以使用此功能检索首选课程的数据。
使用意图可能会像：
Intent intent = new Intent(trackWalk.this,walkHistory.class);
intent.putExtra("MYDATA",//your data here);
startActivity(intent);
on onCreate上的walkHistory类：
//(or another type of variable, it also works for integers)
String steps = getIntent().getStringExtra("MYDATA");
//manage your data here
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